The Man Who new Infinity: Life of the genius Ramanujan by Robert Kanigel
Very little technical detail about his various theorems and contributions, but a great biography of the man and his life, with loads of historical information about India and the British Raj at the end of the 19th century. As a resident of Cambridge, it was great to hear the interlinking story of G.H Hardy, his time at Trinity College, Cambridge and his reforms of the mathematical Tripos.
The author gets into Ramanujan’s character, seeking to explain his motivations and frustrations at not being able to do full time mathematical research, and also seeks to explain Ramanujan’s bodily breakdown when he eventually reached Cambridge. In many ways a sad story, but a very interesting read.