This book is literally described in its title: 100 drawings and sketches that illustrate and capture movement in the human hand.
The hand is notoriously difficult to 'get right' and a sense of the anatomy is essential for understanding exactly what one is looking at.
I don't always find it easy to follow someone else's drawings - after all there to depict - and I find some drawings in this book more useful than others.
Never-the-less, the drawings repay careful study and, put together, you feel someone exploring the structure and movement of hands in great depth.
Couple The Book of a Hundred Hands by George B. Bridgman with your own eyes and you have a very useful resource for getting hands right!