Very simple, and very practical.
I initially wanted a very quick and simple overview of how and why one would raise a child with minimal use of diapers. This book seemed a little overkill, and it was a little longer than what I needed; but it is written for a very lay audience, making it easy to skim the second half of the book, when the main points had already been made.
It also gave me exactly the impetus I needed to actually try out the potty for my son, then just over 2 months old. We have had the potty since before he was born, but I always put off using it; how do I hold him? how do I know when to use it? can I do anything wrong? Of course, I didn't actually need an entire 230 page codex to answer these basic questions, but the first morning I finally got around to opening the first page, it quickly gave me everything I needed. The author made it clear that starting sooner is usually easier; but quickly assured me that any time before three months was a great time to start (babies start losing some basic reflexes around month three, though a little parental perseverance goes a long way until 6 months -- after which the experience might be more frustrating). She soon started explaining how to hold the baby, with accompanying drawings and reassuring suggestions for any possible worry ("don't worry much about hurting him -- babies are tough!", "pee splashes everywhere? Just use one finger to aim his penis, as shown on this drawing."). Timing can be difficult, and optimally relies on cues from the baby; but "right after waking" and "right after feeding" were given as particularly opportune times.
Well, I was reading this early in the morning; and shortly after finishing "Chapter 4: Getting Started" I was called upon from the bedroom to help out with our young one, who had just woken up after his morning milk. I felt like I already knew everything I needed, so I gave the theory a shot -- and succeeded on the first try! (Although the shot somewhat missed its target, forcing me to quickly clean the floor.) Although I don't really have a strong ideological apprehension towards diapers, this early victory motivated me to read through the rest of the book and to regularly offer my son the potty.
Chapter 2 gave me a crash course in the biology of human digestion, and I am now more comfortable with previously hazy words such as "sphincter" and "colon". The author also went quickly over the history of potty training infants, and reasons why parents might want to do it (she is not preachy about this, or about nearly anything else; but as you can imagine, the word "landfills" appears regularly). But this book is really not focused on theory, so this part of the book mostly served as an introduction.
The bulk of the book is practical advice for every conceivable combination of familial circumstances, including for parents who start from day 1 and from day 366. I skimmed a lot of this, but apart from useful potty advice, there was a lot of useful general parenting advice spread throughout. Concepts like "insisting" without "badgering", and teaching a baby through "impacts" (sudden and surprising interventions that make the child focus immediately and intensely), seem applicable to many situations.
Overall, this book was useful and interesting, and it covers every practical base. I still feel I personally might have been just as well off with a well-designed pamphlet; I usually expect more rigor and theory from a full-length book. Most people will want to skim or skip large parts of it. But it is an easy read, and a good choice if you just want to get started.