Relativity: The Special and the General Theory (German: Über die spezielle und die allgemeine Relativitätstheorie) began as a short paper and was eventually published as a book written by Albert Einstein with the aim of explaining the theory of relativity.

. . . an exact insight into the theory of relativity to those readers who, from a general scientific and philosophical point of view, are interested in the theory, but who are not conversant with the mathematical apparatus of theoretical physics.

— from the Preface

It was first published in German in 1916 and later translated into English in 1920.^[1][2][3] It is divided into three parts, the first dealing with special relativity, the second dealing with general relativity, and the third dealing with considerations on the universe as a whole. There have been many versions published since the original in 1916, the latest being in 2015. The 2015 publication by Princeton University Press, is billed as the 100th Anniversary Edition, and was issued as an e-book in 2019.

People such as Robert W. Lawson have called the work unique in that it gives readers an insight into the thought processes of one of the greatest minds of the 20th century.^[3]