Anatomy for the Artist, Sarah Simblet and John Davis (DK Publishing, 2001)
This is a magnificent book, featuring more than 250 photographs and 100 drawings depicting the human body in various poses, while focusing in on various parts in detail.
How to Draw Manga: Bodies & Anatomy, Society for the Study of Manga Techniques (Graphic-sha Publishing, 2002)
This book teaches you how to draw characters in the manga style, but it does so using some of the best and most useful illustrations I have found. Not only are these images clean and well drawn, they also examine parts of the body from different angles and poses.
Dynamic Anatomy, Burne Hogarth (Watson-Guptill Publications, 2003)
Hogarth has a unique style of drawing, one that demonstrates particularly well the surface features of musculature for figures in motion.
Human Anatomy for Artists: The Elements of Form, Eliot Goldfinger (Oxford University Press USA, 1991)
If you're looking for an anatomical reference with a medical emphasis, this is it. Goldfinger's book examines every muscle in the body individually, covering structure, function, and relation to the body as a whole.
Strength Training Anatomy, Frederic Delavier (Human Kinetics Publishers, 2001)
Strength Training Anatomy was created as a guide for weight lifters to show exactly how certain exercises were affecting muscle shapes and structures. For artists, the book is an excellent visual cue for how muscles work in relation to each other and how their shapes change in different circumstances.
Bridgman's Complete Guide to Drawing from Life, George Bridgman (Sterling Publishing, 2003)
Bridgman's approach to drawing focuses on structure, body mechanics, and rhythm lines.
Cyclopedia Anatomicae, Gyorgy Feher and Andras Szunyoghy (Black Dog and Leventhal Publishers, 1999)
Containing pencil drawings of human and animal bones and muscles, this is one of the reference books of choice for creature TDs.