Scientific Soapmaking is a book that takes soap very, very seriously. It's dense with information, but that information may not be exactly what you expect. While a lot of the book does indeed cover the underlying chemistry of soap and tackles some of the important issues soap makers face, a huge portion of the book is all about doing your own experiments. The entire first third of the book is teaching you how to make small (1-bar), highly accurate (measuring ingredients in grams to two decimals out), quick-turnaround (you're buying a roasting oven to speed things up) test runs.
This degrees of accuracy and reproducibility is such that I can only imagine a full-time professional being interested in jumping through these hoops to get there. The problem is that he doesn't gear the book just towards professionals, or even experienced soapmakers; he tries to bring beginners - who have never made a bar of soap, let alone used a lye calculator - up to speed. Beginners who have never made soap before should not be relying on this book to get them started: he asks you to make a substantial investment in equipment, chemicals, and time (leaning how to do things in very specific ways) when you don't even know you're going to like the hobby or stick with it. He should have started with the assumption that anyone who would want to pick up this book has made soap already. The book grinds to a halt every time he starts talking about why you have to mix oils for the best results or what a slab mold is. Everyone who has read another soap book knows what coconut oil brings to the party, how to use an online lye calculator, and they've probably made their own castile at some point, so stepping slowly through these issues like you don't know a thing about them becomes tedious.
I suppose he's trying to be inclusive of beginners to make the book suitable for students in a chemistry class. Not only does he guide you through a bunch of experiments, a lot of them aren't even soap-related. The first part of the book leads you into soap chemistry by asking you to perform a whole series of experiments with acids, bases, alcohols, and more. There are also "Practice Problems" at the end of the chapters. I skipped all this and decided to just take his word on the fact that Xg of acid would neutralize Yg of alkalines. I'm a hobbyist soap-maker and I do this for fun: I didn't want to run my own experiments, I just wanted to know the results of his.
All this chemistry talk does eventually lead into what I was really after: namely, what happens when lye meets oils. And I was excited when a couple of big, fat light bulbs went off over my head. I learned about rancid oils, what happens during the curing process, and why Castor oil behaves differently than everything else. Once I slogged my way through a bunch of skippable math instruction and background info, things got much more informative.
Finally, the very back of the book is where he answers the questions a soap maker is really after. Soda ash, DOS, lye discounting vs superfatting, water discounting, temperature changes, and more have been tested and laid out in charts.
My final verdict? Professionals should probably own this book, and hobbyists would benefit by reading through it at least once. There's some very good information in the pages, but an average soap maker can skim half the chapters, skip the experiments, and ignore the instructive problems. I suppose this book is also written for classroom instruction, but the very things that make it a good introductory textbook make it a slow, frustrating book for soapers. Still, I'm a soaping hobbyist myself and I'm glad I bought the book.