This book is great. Firstly, the illustrations are beautiful - please note that these are not photographs like some other books, but rendered art. This however makes it easy to understand, and not be distracted by the photography.
This book contains so many fashion details - different eras such as the 50's and 30's and some typical features, the visual effects of using the bias, hemlines, straps, frills, ruffles... and the best bit - it helps you draw them better to present to clients/professors. This is great if you are trying to improve in this area as it has very professional illustrations that you can analyze to understand how and why they have been presented in such a way so that you can apply it to your own illustrations to make your details look better (e.g. ruffles, cuffs, etc)
As a designer I find this inspirational and a great reference book for considering details. It does not cover construction, pattern making or anything else other than illustrations of different styles. But that it does exceptionally well and very thoroughly. A great addition to a personal library.