Some parts of this book haven't aged well. Other parts are timeless. Published in 2008, that's 17 years ago (currently mid-2025).
The author seems to think that photovoltaic solar cells have no future. Back in 2008, most of the solar cells on offer were monocrystalline cells which were sliced from ingots of super-pure silicon and processed in clean rooms. Purifying the silicon, casting the ingots and setting up a clean room which will remove even nanoscale pollutants, such that you can use semiconductor fabrication processes to turn the material into the cells, all require significant energy; the author is perfectly correct about that. Some of the solar cells being made back then were barely paying back the energy it took to make them; the author pointedly calls that out. He's not wrong. The author's talk about the need to consider "net energy return" (sometimes known as Energy Return On Investment or EROI) is one of the timeless parts.
String Ribbon tech really changed PV production, greatly reducing the energy required for manufacture. Modern thin-film PV has considerably lower energy requirements in manufacturing. Some of the dye-sensitized thin-film organic stuff needs a small chamber and multiple types of applied inks, no high-temperatures, ultra-pure silicon or clean rooms. Many of the solar panels being sold today pay back their energy investment within 12 months of installation, and they keep going for 20+ years. This puts their EROI at 20:1 or so. Eliminating the need for the energy-intensive processes makes it more likely that we'll be able to continue making such things, going forward. Ergo, I don't think his pronouncements about PV have aged well. No, we won't be able to replace all of the coal-burning powerplants, nuclear powerplants, petroleum-fueled transportation, etc. with solar any time soon; PV solar is NOT a drop-in replacement which will let us keep doing what we're (currently) doing. On that count, I do agree with him.
Back when he authored this book, it seemed ethanol was barely breaking even, in terms of EROI. These days, it's at least 1.5:1 on EROI; some forms of it are over 2:1. For a long time, it appeared that it was net negative. Then someone took a closer look at the researchers who were saying it was still net negative and discovered that they'd hadn't bothered to update their figures on energy inputs (assuming that farmers were still using the same equipment, fertilizers, seeds and processes as in the 1950s) and debunked their more recent works. That's when it was discovered that, yeah, ethanol has been break-even or better for a while. I don't know that the debunking had happened before this book was penned. The author is right that biofuels, such as ethanol, aren't going to provide the 200:1 EROI that we were getting from petroleum back in the day. But then, modern deepwater oil production, and fracked oil production, isn't getting that 200:1 EROI anymore. That fits perfectly with his main thesis: we've passed the age of cheap energy (oil production in decline, no drop-in replacements, etc.) so we need to start thinking about how we're going to downscale our consumption, our lives, our civilizations, etc. because our entire way of life, for multiple decades, has been built on cheap energy which is ceasing to be cheap.
I cringe when I think about the 12 MPG monstrosity I was driving when I first got my license; my current hybrid gets 36 or so, and I'm really wishing I had PHEV so I could do at least my local errand-running without burning fuel at all. I'm also wanting to get an e-bike (much more likely than the PHEV; order of magnitude cheaper). I've moved away from a rural area, as I recognize that anyone needing to burn multiple gallons of gasoline, per day, just to run errands and get to / from work ... that lifestyle is doomed. I agree with him, completely, on this count. I'm currently in the process of pivoting my career and ... ya know, being able to repair electric appliances, maybe sewing machines ... those are useful skills and there are too few people doing it now (check with any sewing supply place and they'll tell you that getting machines repaired takes a while 'cuz lots of demand for same but little supply; my beloved sews, which is how I know). Keeping extant equipment running longer is a useful thing. Sewing is more likely to come back into vogue, as shipping "fast fashion" clothing from China on petroleum-fueled container ships becomes too expensive.
The author also leans into what we need to provide for future generations, in terms of skills, materials and knowledge. He explains that there have been attempts, in times past, to compile some kind of "here's everything you need to know" type books and ... they've been boondoggles. In the 1920s, who would've seen computers, the Internet, multiple World Wars, etc? What advice could they have given to their descendants which would actually be useful? Sure, there is some knowledge from that era which is still relevant but it's probably NOT the stuff that people, at that time, would've thought relevant. So we need to provide not just data, but guides on how to explore, test and measure data, so future generations can continue to apply the Scientific Method and related things.
He also leans into psychology, myth and beliefs. Another, much lighter book I've read ("Change the Story, Change the Future" by David Korten) leans into this as well. So long as the ideal is growth, growth and more growth, which is simply not possible (long-term) in a finite environment, people will do anything and everything to keep the most popular modern religion ("progress;" what, you thought I was going to say Christianity? that's not even one religion ...) in vogue.
In the most recent US Presidential election, the Democrats were talking about how the economy is doing well, unemployment is down, the worst of the inflation is behind us; stick with us, because we're why things are going well. The Republicans were doing their usual "the world will end if THEY stay in power" and offering a buffoon who was promising to tear it all all down. Most people either embrace a "progress" view of religion (things are getting better and better, until you get to heaven) and others embrace an "apocalypse" view of religion (someone else is benefiting and you will never get anything better under the current system; destroy it all and you will finally have your chance). Most people in the USA are NOT seeing their lives getting better; a considerable fraction is facing the fact that they will never have enough economic stability to buy a home, never be able to retire, never be able to afford having children. Such people are not going to embrace an "all is well" message; a slim majority (49.8% vs 48.3%) chose apocalypse. I can only hope those reading this in the future can look back on our current predicament and sigh with relief.
The reality is that neither party is willing to tell the public that the best days, the most luxurious days, are behind us for the vast majority of the population, and we better get busy battening down the hatches, tightening our belts and learning how to grow food organically because ... petroleum-based fertilizers and pesticides, as well as petroleum-fueled heavy industrial farm equipment, are going to become unobtainium. Along with road trips to Disneyland. And flying to the Caribbean on vacation. And ... hell, easily 50% (or more) of the current jobs out there today. Too many modern corporations depend entirely on cheap energy; when that no longer exists, there will be a dearth of openings for jobs that only exist in large corporations. How many "marketing directors" does a such a world need?
Another book I've read recently ("2052: A Global Forecast for the Next 40 Years" by Jørgen Randers) explains that the reduced availability of cheap energy was, originally, foreseen by various computer models back in the 1970s and reported in "The Limits to Growth." This book references the same report. All of these books expect global population to peak and start falling; the only question is what year will be the peak. So much of modern life depends on cheap energy; when it ceases to be cheap, fewer people will reproduce (already happening; the fertility rate, in most countries, is below the replacement level) and average life spans will reduce (life expectancy been stagnant, if not falling, for a while; USA life expectancy peaked in 2014). The population will shrink until it's something which will fit within the finite resources of our finite planet. We've been in a state of overshoot for multiple decades. Things will get genuinely crappy for a while, then they'll seem to level off (whew!), maybe even improve a little (yay!), then sink considerably more. The future is a stair-step, over the course of centuries, down to a more agrarian, smaller-scale world. Star Trek, where we go to the stars and expand forever and ever amen, is not in our future. Nothing wrong with being entertained by the fantasy; just remember that sci-fi is fiction that's somewhat science-y.
Note: do NOT overlook the appendices in the back of this book. There are some very interesting things in there, just don't be scared off by a little math.