The mechanics underlying the form and structure of biological tissues is being increasingly investigated and appreciated, with new results appearing at a fast pace. Cellular Patterns covers the salient elements of this thriving field of research in a textbook style, including both historic landmark results and recent achievements. By building on concepts such as packing, confinement, surface tension, and elastic instabilities, the book explains the structure and the shape of sheet-like and bulk tissues by adapting the mechanics of continuous media to living matter. It reviews experimental results and empirical laws, and wherever possible, it discusses more than a single theoretical interpretation of a given phenomenon. The in-depth treatment of technical details, the many boxes summarizing essential physical and biological ideas, and an extensive set of problems make this book suitable as a complementary textbook for a graduate course in biophysics and as a standalone reference for students and researchers in biophysics, bioengineering, and mathematical biology interested in the mechanics of tissue.