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

For a book ostensibly about advanced mathematics and number theory, The Man Who Knew Infinity strikes an incredibly light and conversational tone. he author is more interested in the story of the two men involved, Hardy and Ramanujan, than he is in the math itself. Instead of a dry explanation of strange concepts in mathematics, we find a brisk and interesting history of English mathematics and academia in the early twentieth century as well as a portrait of colonial India. The prose is easy to read and the story moves along at a pace that will encourage even those who lack all interest and knowledge of mathematics.