<human>:  What is the name of the man who knew infinity in the book ‘The Man Who Knew Infinity Bright, John’?
<bot>: The man who knew infinity was Srinivasa Ramanujan. Ramanujan was a brilliant Indian mathematician who died in 1920. He worked with numbers that were so big that it was impossible for anyone to calculate them with pen and paper. His work was discovered after his death, and it is still studied today.