"This book provides a thorough treatment of the Assouad dimension, as well as its many variants, in the context of fractal geometry. The book is split into three parts. In the first part, the basic theory is set up including how the various dimensions relate to each other and how they behave under Lipschitz and Holder mappings. In the second part, many examples are discussed including self-similar sets, self-affine sets, limit sets of Kleinian groups and Mandelbrot percolation. In the third part, several applications are discussed including to problems in number theory, embedding theory, probability theory and functional analysis. Several open problems are discussed at the end"--