The Microbiome Master Key: Harness Your Microbes to Unlock Whole-Body Health and Lifelong Vitality

by B. Brett Finlay, Jessica M. Finlay

Learn the secret to whole-body, lifelong health: the teeming world of microbes inside and all around you.

Hand sanitizer. Social distancing. Antibiotics. Fending off germs has long been considered one of the cornerstones of good health. But what if better health and more graceful aging actually went hand-in-hand with embracing microbes?

Your body is teeming with microbes—not just in the gut, but also on your skin, in your lungs, and beyond. And they impact everything from your sleep, cognition, mood, heart health, and energy to your likelihood of developing many diseases. As groundbreaking new studies are showing, taking care of your microbiome—inside and out—can help you improve your day-to-day health and even help prevent or reverse some of the most common age-related diseases.

This eye-opening book breaks down what the latest research says about how the microbiome affects all aspects of physical and mental health—and what you can do about it.

Potentially change the trajectory of 9 out of 10 leading causes of death, including heart disease, cancer, lung disease, stroke, Alzheimer’s disease, and diabetes
Increase your resistance to pathogens like the flu and COVID-19
Keep your skin soft, healthy, supple, and less wrinkled
Stabilize your weight and control blood sugar
Improve your physical fitness and strength
Fight “inflammaging”—low-grade inflammation that hastens the aging process
Get a more restful and rejuvenating night’s sleep
Reduce stress and improve mental health—and your long-term quality of life

The Microbiome Master Key is an updated and expanded new edition of The Whole-Body Microbiome.

Genres: Health, Nonfiction, Science, Biology, Self Help, Medicine, Nutrition

352 pages, Paperback

Published July 1, 2025

About the author

Dr. B. Brett Finlay is a Professor in the Michael Smith Laboratories, and the Departments of Biochemistry and Molecular Biology, and Microbiology and Immunology at the University of British Columbia. He obtained a B.Sc. (Honors) in Biochemistry at the University of Alberta, where he also did his Ph.D. (1986) in Biochemistry under Dr. William Paranchych, studying F-like plasmid conjugation. His post-doctoral studies were performed with Dr. Stanley Falkow at the Department of Medical Microbiology and Immunology at Stanford University School of Medicine, where he studied Salmonella invasion into host cells. In 1989, he joined UBC as an Assistant Professor in the Biotechnology Laboratory. Dr. Finlay’s research interests are focussed on host-microbe interactions, at the molecular level. By combining cell biology with microbiology, he has been at the forefront of the field called Cellular Microbiology, making several fundamental discoveries in this area, and publishing over 460 papers (h index=110). His laboratory studies several pathogenic bacteria, including Salmonella and pathogenic E. coli, and more recently microbiota. He is well recognized internationally for his work, and has won several prestigious awards including the E.W.R. Steacie Prize, the CSM Fisher Scientific Award, CSM Roche Award, a MRC Scientist, five Howard Hughes International Research Scholar Awards, a CIHR Distinguished Investigator, BC Biotech Innovation Award, the Michael Smith Health Research Prize, the IDSA Squibb award, the Jacob Biely Prize, the prestigious Canadian Killam Health Sciences Prize, the Flavelle Medal of the Royal Society, the Queen Elizabeth II Diamond Jubilee Medal, the Prix Galien, is a Fellow of the Royal Society of Canada and the Canadian Academy of Health Sciences, is a Member of the German National Academy of Sciences, American Academy of Microbiology, Chair d'État, Collège de France and is the UBC Peter Wall Distinguished Professor. He is an Officer of the Order of Canada and Order of British Columbia. He is a cofounder of Inimex Pharmaceuticals, Inc. and Microbiome Insights, scientific cofounder of Vedanta Pharmaceuticals and CommenSe, Director of the SARS Accelerated Vaccine Initiative, and Founding Director and Senior Fellow of CIFAR’s Microbes and Humans. He also serves on several editorial and advisory boards, and is a strong supporter of communicating science to the public.

Reviews

[Rachelle · Rating 4 out of 5]

Fascinating stuff. I will be interested to see where science goes with the microbiome in the near future. Maybe it will bring a cure for my allergies! I have completely overhauled my diet to focus on my gut microbiome and would like to figure out options for skin care too. A star removed for a lack of resources or recommendations, though that might be unfair. I just wanted a bit more.

[Alanna · Rating 3 out of 5]

2.5 ⭐️🎧 This book took me montthhssss to get through. Rounding up because I’m excited for the future of microbiome research and hope it continues to be a field that people study. However, this specific book shared no insights that were new to me.

[José Angel Hernández · Rating 5 out of 5]

For someone who is not a scientist nor has ever taking any science courses in college , except for those that were required to get the degree , this book was very easy to follow and had a significant impact on my thinking . i am not easily influenced by what i read because i read so much and , as a social scientist , the one thing that we are taught quite effectively is critical thinking and comparative analysis . this book does an excellent job of taking the lay person through the literature without getting bogged down by medical terminology , and when medical terms are employed , the authors are kind enough to add a parenthesis and to say something simple and practical about said terminology.

in a nutshell , what the book does this provide a history and also a contemporary analysis of recent discoveries and studies of the microbiome, and then it takes this analysis several steps forward by talking about recent applications where these technologies are being employed by companies and doctors . it also goes even further by giving practical tips about what foods have probiotics and that are beneficial for health and longevity.

one of the fascinating things about the book , amongst the many fascinating tidbits that the book offers , was the discussion about fecal matter transfers and how the chinese had been employed some of this microbe technology in the 4th century . the arguments that the authors made about fecal matter transfers are convincing and made me ponder the many possibilities of transferring the microbiota of someone's microbiome to that of a person whose microbiome was in need of a much healthier transplant .

in all, i would highly recommend this book to anyone that is looking for a fascinating read on current medical technologies , on the use and discovery of microbial technologies, and on some great ideas about what products and foods one should use in order to maintain healthy living and a healthy microbiome...

[Dawn Peterson · Rating 4 out of 5]

This book was quite an exercise. I read much of it out loud to whomever was sitting near me.

2 things to know about me:
1) I have some germophobic tendencies: I cannot eat lunch at the zoo. If we meet for lunch and you quickly pop into the bathroom with your to-go container before you head home, we cannot be friends anymore. If my toothbrush touches a hotel counter, I need a new one. I love essential oils, but I cannot find any combination as soothing and calming to me as chlorine bleach.
2) I roll my eyes at food fads. Whatever the social influencers are eating and drinking because it's so cute or fun or it's curing their inflammation-- I laugh at their reasons and ignore them.

After reading this book:
I'm re-thinking some of my cleaning supplies and habits. I'm allowing my dog to lick me. And I have my first batch of kombucha brewing. Because Science.

So yeah... I picked up what the authors were laying down.

[Joshua · Rating 3 out of 5]

In between book. Explored interesting potential for application. But as someone who has already read up on this subject it didn't provide anything new. Eat well, exercise, have some prebiotic foods, maybe some probiotics, and don't be too clean. There were a few whole chapters exploring the microbiome in various organs but of which studies are limited.
Perhaps a good reminder/intro book for some.

[Paul Sutter]

There are many books out there that advocate ways to live longer and better through some basic changes in your lifestyle. Some work, some don’t. It is obvious that with THE MICROBIOME MASTER KEY, we have the roadmap to live long and prosper to take the words of a famous character from the sixties.
The father and daughter team of Brett and Jessica Finlay, have laid out the basic principles to help incorporate the vast amount of microbes within our body, to create the path to living longer and have less stress and mess within your body. The book certainly talks to the level that people can understand, and find useful in their lives. The microbes within our body can help do so many positive things, and they are laid out brilliantly within the pages of the book.
It looks into the world of the microbiome, and the many studies that have been created because of it, studies that have shown countless benefits on so many fronts. The main thing is by employing microbes into our life and daily routines, will reap benefits of the highest order. It will give us not a new body, but a new outlook on life, by adding them to your diets and actions that we take.
Some of the advice is common sense and knowledge, but it doesn’t hurt to have them reinforced throughout the book, such as the dangers of smoking, getting the proper amount of rest, eating the right fats, adding probiotics to our diet, avoiding processed foods, keeping weight and intake of sugars under control, and well, so much more.
No matter what the age or lifestyle, we can do positive things in regards to our overall health and that will improve our outlook on life. Plus it will help as we face the potential for possible life-changing and life-ending diseases as Alzheimer’s, cancer, the flu, Covid-19, and many more. The ability to fight back and be more resilient can be achieved by following what is advocated in the pages of the book. This book is a game and life-changer, providing the opportunity to change everything about yourselves from the head down.

[Lorena · Rating 5 out of 5]

This book provides a broad overview of research on the human microbiome and how it affects health and aging. It gets a bit technical at times, but is well organized, interesting, and easy to understand. I appreciated that the authors are clear about what we know, what we suspect, and what remains unknown.

Each chapter discusses the microbiome of a different organ or system, summarizing results from current research, discussing areas where future research might be most helpful, and providing helpful suggestions for how to make use of this knowledge. Each chapter ends with a section of quick tips summarizing their recommended actions and a list of selected references. There is an index at the end, which I have not had a chance to review.

Many of the health recommendations are going to sound familiar, but I appreciated getting a new understanding of why these recommendations are so important. For example, after reading about the oral microbiome, I am feeling a lot more urgency to brush and floss my teeth more often and to pay attention to what is in my toothpaste.

I would recommend this book to anyone who enjoys reading about medical research. If you don’t think you would enjoy reading about studies conducted on germ-free mice or learning about how bacteria influence the levels of cytokines that affect inflammation and the immune response, then this may not be the book for you.

I was provided an unproofed ARC through NetGalley that I volunteered to review. Because I have not seen the final published version, I cannot comment on the final editing and formatting.

[Erin J. · Rating 5 out of 5]

I never realized how much the microbes inside and around me were shaping my health until I read The Microbiome Master Key. This book is a fascinating, science-backed journey into the tiny organisms that impact everything from sleep, energy, and mood to heart health and immunity.

The authors make complex science easy to understand and provide practical tips you can immediately apply to support your microbiome. From improving digestion to fighting “inflammaging” and even boosting mental clarity, this book is empowering.

Whether you’re a health enthusiast or just curious about how your body truly works, this book opens your eyes to the incredible power of microbes. I finished feeling motivated to make small, actionable changes that could transform my health for years to come.

A must-read for anyone looking to unlock their body’s full potential and take control of lifelong wellness!

[Nicole Nygard · Rating 5 out of 5]

This book taught me so much. I’m very interested in the gut and body connection and this book gave me everything I was looking for. There are definitely some technical (over my head) sections that dig into the biology and science, but I think the authors did a great job of breaking that down into layman’s terms. I did a GI Map test right before reading this book and I could connect so much to that test and felt like I understood my body better. They dig deep into the different bacteria living all over in your body (your mouth, your vagina, your brain, etc). For anyone that may not have a degree in health or science, but want to fill that void of not understanding your body, I would suggest reading it. It can be overwhelming, because you can’t possibly change everything, but it will absolutely enhance your knowledge in this area.

[Gemini · Rating 5 out of 5]

While this book is pretty long, it's well worth it. The amount of knowledge that is given by the author is simply amazing. There is so much to know, which isn't always easy to understand. Even though there is sciencey stuff in this book, it's definitely worth checking out. These are not things you learn in school or from your doctor or nutritionist/dietician shares w/ you. It's a wealth of information that everyone should know about. It's so important to see how not only is everything connected but how your body (gut) reacts to all the things you consume. Simply fascinating. I mean it's literally a whole ecosystem of microbes, like wow. How often do you even think about it, let alone have a conversation about it? This is the type of stuff people should learn about; they would maybe think twice about what they eat. Go read & share.

[Alex · Rating 5 out of 5]

Very informative and full of referenced research.

Especially useful for me is page 136 entitled, "The Personalized Microbe Diet." Research went into determining specific gut composition of participants that included tracking ingested foods with their specific corresponding glucose spikes. Digestion problems and food reactions are like fingerprints; individuated. Once a person knows their flora composition, they can tailor a diet that best fits their specific digestion needs. The very best part of 136 is finding out the name of a company, DayTwo, that offers microbiome testing with corresponding dietary recommendations. Since the publishing of this book, probably even more are sprouting up.

Thorough and civilian friendly read.

[Andrea Wenger · Rating 5 out of 5]

This book explains how understanding your microbiome can contribute to lifelong health. Nurturing the microbes inside and around us can revolutionize physical and mental well-being, potentially preventing or reversing age-related diseases and boosting overall quality of life. The book is interesting, informative, and easy to understand.

Thanks, NetGalley, for the ARC I received. This is my honest and voluntary review.

[Jo-Ann Houde · Rating 2 out of 5]

I got about half way through this audiobook and had to abandon it. It was dry and technical and didn't hold my interest. The information presented was consistent with what I've read in other books, so it just wasn't worth my time to continue reading. If anyone is looking to pick up a book on the subject, I found "The Microbiome Solution", by Robynne Chutkan to be a much better read.

[Ginger Essink · Rating 4 out of 5]

This was a fascinating book--I've been reading a lot about the gut microbiome, but didn't understand that so many parts of the body have their own microbiomes, though all are related to the gut. This whole area makes the future of managing chronic disease seem more hopeful. There are so many new options on the horizon.

[Judi Koch · Rating 3 out of 5]

Interesting but based on preliminary research. There's still a lot of conjecture and unknowns about the science.
It was recommended by my PA. Not exactly earth shattering, but nicely layout the interconnectedness of our overall, full-body health with the composition and function of our gut microbes.

[Mike · Rating 3 out of 5]

It was interesting to learn about the Microbiome and how it affects you, but it seemed a little too technical at times. I expected to get more useful information out of it than be sure to wash my hands. I found parts of it very good, but it did seem a bit redundant.

[Suresh Rangarajan · Rating 4 out of 5]

Great read on microbes, especially if you missed the recent big hits.
Lot of new information, well laid out
Sad part is: plenty of research on microbes is in early stages and pretty much inconclusive

[Adrienne DeLuca · Rating 3 out of 5]

Only got half way through and had to return to library. It was very simplistic and not a lot of research has come forward just yet to prove a lot of the theories, but cool read if you don't know a whole lot about the microbiome (but I do, which is why it was kind of an eady read )

[Hannah Comstock. · Rating 3 out of 5]

Found this to book to be informative to a certain extent. However, it became redundant in later chapters. The underlining message being to eat a more fibrous diet, exercise often, and limit alcohol consumption and smoking.

[Anna Funk · Rating 2 out of 5]

Eh, I'm shelving this. Wasn't what I expected. The whole thing is framed as "anti-aging" (which is fine, but not what I expected based on the cover/title). Prob would be more interesting if you're totally new to the microbiome scene and just want the basics. Made it to page 100 (of 300).

[Curtis Mah · Rating 3 out of 5]

Not bad, but I am hoping for a follow up.

Much of the research in this book is very preliminary and only done on mice thus far.

Hoping for a second version in a few years when more research on the gut biome, FMT, and probiotics is complete.

[Megan · Rating 3 out of 5]

Lots of interesting information, but I ended up skimming a lot of chapters. The practical information just wasn't that helpful, beyond the general advice to eat a varied, plant-heavy diet and move your body regularly.

[Amber Hawes · Rating 3 out of 5]

This book had a lot of good pieces of information, but some chapters were much more interesting than others. I really appreciated the "myth vs. fact" and "quick tip" elements included in each chapter as they really underlined the most important takeaways.

[Alexis Reyes · Rating 4 out of 5]

Informative read about the emerging research behind microbiomes and health benefits. Will be exciting to see if some of these recommendations become standard practices for optimal health and longevity over the next decade.

[Sharon · Rating 3 out of 5]

Some good information about the micro biome. I feel that some of it is already outdated because things are moving so quickly in this discipline. I think that if we focus on eating a whole foods plant-based diet we’re already 99% of the way there. Processed foods are poison.

[Janet Mercer · Rating 3 out of 5]

Interesting and exciting how our microbiome effects our health and well being, and how it could change how medical conditions are perceived and treated.

[Emily Kerbuski · Rating 4 out of 5]

Informative and engaging. Evidence based with cited sources that are easy to reference.

[Hazel · Rating 3 out of 5]

Good read! Some speculative science here as we still need more studies and data to really finalize some of these theories. Very interested in seeing where the field goes.

[Kendall Aardema · Rating 4 out of 5]

A good introduction to the microbiome and its relation to the human body - it had a few good tips, but some of the studies were limited. Still an interesting and easy-to-read book!!

[Lara · Rating 3 out of 5]

Like many of this genre, it makes a book out of something that could have been an article.

Bottom line: eat fiber!