I've read a lot of anatomy books, Bridgeman, Loomis, Hogarth, etc. but I think the Holy Grail just might be SECRETS OF DRAWING, a new book by fantasy and comics artist Mike Hoffman.
This is a slender and simply-written book full of easy-to-understand practical tips that are as eye-opening as they are essential. In addition, the drawings are undeniably solid, loaded with life and appeal. The illustrations highlight as clearly as possible each tip and the plain-spoken text reinforces the art as clearly and concisely as anything I have read. Many books contain either one or the other (as in good tips/mediocre art or great art/vague text)--this book is hits a bull's eye for both targets. I've taken many good figure drawing classes and learned much from instructors, but this book broke through decades of problem areas in figure drawing for me that no amount of practice or study has to date.
Quick gesture drawings have always come easily to me, but in fine-tuning an image I have often got lost or fouled up by innate misunderstanding of an inherent form or concept. Not even knowing exactly why makes it even harder to correct. This is the book that nailed some simple but universal "rules of thumb" for solving those errors. Though I am not an aficianado of comics, I looked up checked out the artist's website and highly recommend it. I'd call the book a must-buy and the price is highly affordable.