A little out of date now, but much of the information is essentially true since it ic mostly empirical relying mostly on the evidence of person's experiences. There are possibly too many testimonials in the book but not enough analyisis. Some of the re-feeding strategies would not now be recommended since we live in a dystopia of type2 diabetes, fatty live disease and obesity. In particular the recommendation so t drink fruit juice is not a great idea as most people looking into fasting would be interested because they have a diagnosis of pre- or post diabetic. But if you want a boost of reassurance to give fasting a try. This book will do that. If you want to know what science has added in the interveneing period, read Jason Fung; The Obesity Code; Diabetes Code; or Hunger Code..
Or if you want a lighter read and a list of methods, tips and tricks "The Complete GUide to Fasting" aslo by Fung is where to go next
I start my review with three warnings. First, nearly all diets are rubbish. Some people are naturally fatter than other people but no diet (that I'm aware of) targets the real causes of obesity: genetics, stress, poverty, illness, etc. Second, this book was written over 35 years ago. The science in it is outdated. Third, if you are buying this book to loss weight: don't. You are beautiful no matter what you weigh. There are many ways to stay healthy without indulging in eating disorders.
That said, I bought this book as a teenager to learn how to fast for religious purposes, because I couldn't find anything else. As a how-to, it served its purpose.