In this book, the author applies non-associative algebras to physics. Okubo covers topics ranging from algebras of observables in quantum mechanics and angular momentum and octonions to division algebra, triple-linear products and YangSHBaxter equations. He also discusses the non-associative gauge theoretic reformulation of Einstein's general relativity theory. Much of the material found in this volume is not available in other works. The book will therefore be of great interest to graduate students and research scientists in physics and mathematics.