The Indian clerk - David Leavitt

On a January morning in 1913, G. H. Hardy - eccentric, charismatic and, at thirty-seven, already considered the greatest British mathematician of his age - receives a mysterious envelope covered with Indian stamps. Inside he finds a rambling letter from a self-professed mathematical genius who claims to be on the brink of solving the most important unsolved mathematical problem of his time. Some of his Cambridge colleagues dismiss the letter as a hoax, but Hardy becomes convinced that the Indian clerk who has written it - Srinivasa Ramanujan - deserves to be taken seriously.

Aided by his collaborator, Littlewood, and a young don named Neville who is about to depart for Madras with his wife, Alice, he determines to learn more about the mysterious Ramanujan and, if possible, persuade him to come to Cambridge. It is a decision that will profoundly affect not only his own life, and that of his friends, but the entire history of mathematics.