Albert Einstein 
Relativity: The special and the general theory 

Relativity: The Special and the General Theory began as a short paper and was eventually published as a book written by Albert Einstein with the aim of giving: “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.” It was first published in German in 1916 and later translated into English in 1920. It is divided into 3 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.