The Soapmaker's Companion
The Bottom Line:
If there is any one book which is indispensable to any soapmaker -- novice or expert -- it's this. The Soapmaker's Companion is both an excellent introduction to the topic of making handmade soap from scratch, and an excellent reference for materials, ingredients, and recipes.
The Nitty Gritty:
The Soapmaker's Companion is considered by many soapers to be one of the best books on the topic. It is the first soapmaking book I bought, and still the one I use the most frequently. It contains a full description of many common soapmaking base oils, advice on coloring, fragrance, and designing your own recipes, and it lays everything out in a very clear and understandable fashion.
One of my most often referred-to parts of this book is the section on oil usages. It has between half a page and a page and a half on essentially every fixed oil common in soapmaking, and some not-so-common ones. It also has a quick-reference chart which is a quick reference for substituting in a pinch. She also has a full section on botanical colorants and how to use them, which is quite useful.
This book includes over thirty recipes, tried and proven, for all sorts of soaps under the sun, plus some other goodies. It even covers transparent and liquid soaps, plus marbling techniques and other ways to jazz up your soap with embedded and stamping techniques.
Aside from the content, the book is well-bound and hasn't fallen apart even after being read cover to cover or referred to countless times. The pages are still in excellent condition (no yellowing) after several years and overall, it seems to be a quality publication.