This book review discusses "Theory of Viscoelasticity" by R. M. Christensen, published by Academic Press, Inc. in January 1971. The reviewer, I. B. Freund, highlights the book's value for engineers and researchers interested in viscoelastic materials due to the limited number of comprehensive resources available. The book focuses on the phenomenological theory of viscoelastic materials, emphasizing mathematical aspects and practical applications. It covers topics such as stress-strain constitutive relations, isothermal boundary-value problems, thermoviscoelasticity, wave propagation, general theorems and formulations, nonlinear viscoelasticity, and determination of mechanical properties. Each chapter includes extensive references and exercises, making it suitable as a reference source and potentially a graduate-level textbook. However, the reviewer suggests that a course in linear elasticity and general continuum mechanics would be beneficial before studying this book.This book review discusses "Theory of Viscoelasticity" by R. M. Christensen, published by Academic Press, Inc. in January 1971. The reviewer, I. B. Freund, highlights the book's value for engineers and researchers interested in viscoelastic materials due to the limited number of comprehensive resources available. The book focuses on the phenomenological theory of viscoelastic materials, emphasizing mathematical aspects and practical applications. It covers topics such as stress-strain constitutive relations, isothermal boundary-value problems, thermoviscoelasticity, wave propagation, general theorems and formulations, nonlinear viscoelasticity, and determination of mechanical properties. Each chapter includes extensive references and exercises, making it suitable as a reference source and potentially a graduate-level textbook. However, the reviewer suggests that a course in linear elasticity and general continuum mechanics would be beneficial before studying this book.