What is the theme in The Man Who Knew Infinity: A Life of the Genius, Ramanujan by Robert Kanigel?

Creativity vs. Rigor is a major theme in the book. In The Man Who Knew Infinity, the conflict between creativity and mathematical rigor arises again and again. From Ramanujan's first letter on we are aware of Ramanujan's sparkling and original mathematical creativity. Many of the theorems he sent Hardy were true and original, but they lacked the rigorous proofs that mathematicians require traditionally. Hardy replied to Ramanujan's first letter that proposing the theorems was not enough and he needed to actually prove them.