The book that spawned a sensation with both students and professionals throughout the world, A.C. Fischer-Cripps' The Physics Companion is a revision aid and study guide for undergraduates in physics. It covers the core topics, deriving key concepts and equations in clear one-page figure-rich descriptions. Each subsection contains a summary of the main equations, together with a set of worked examples. The topics covered include thermal physics, electricity and magnetism, waves and optics, mechanics, states of matter, and quantum physics. Intended as supporting material for other texts, the book will be an essential resource for undergraduate students throughout the course of their degree.