The book is an excellent resource on animal locomotion, and very useful right now for our students - who are currently tackling animal and creature locomotion.
Stuart Sumida is a paleontologist who also works in showbiz; he has acted as advisor to countless Hollywood films including Spirit - Stallion of the Cimarron, where he gave extensive talks to the animators (including me) on horse locomotion. To find the free download, follow this link. And to read more about Stuart Sumida's work, see this blog post.
http://www.stuartsumida.com/ANIMATION/LocomotionImages.pdf
