Walking is simple for most of us, but two-legged robots (bipeds) are often slow, complex, inefficient, heavy, and have robotic-looking motions. What makes human walking so graceful? Can this be replicated with human-like robots? Martijn Wisse and Richard Q. van der Linde provide a detailed description of their research on pneumatic biped robots at the Delft University of Technology, The Netherlands. The book covers the basic theory - passive dynamic walking - and explains the implementation of pneumatic McKibben muscles in a series of successful prototypes.