A scientific look at the skill of juggling. For the juggler who's interested in science, or the scientist who's interested in juggling, this is a comprehensive examination by two experts in the field. We look at the pros and cons of different juggling patterns and analyze various constraints jugglers face, including: hand speed, timing, throwing errors, and the spatial constraints of objects in the air. We make some conclusions about optimal patterns, what constitutes good form, how jugglers avoid collisions, and the human limits of juggling. We also look at the many ways jugglers change the constraints to make it more interesting. Other topics in the book include: juggling definitions, different props, historical juggling, juggling records, the physics of thrown objects, Shannon's juggling theorem and other useful equations, juggling instruction, "siteswap" notation, and training advice.