The Inner Circle is a novel by T. C. Boyle first published in 2004 about the development of sexology in the United States and about Alfred Kinsey's rise to fame during the late 1940s and early 1950s as seen through the eyes of one of his loyal assistants.

Boyle makes it unmistakably clear in the "Author’s Note" that The Inner Circle "is a work of fiction, and [that] all characters and situations have been invented, with the exception of the historical figures of Alfred C. Kinsey and his wife, Clara McMillen.

The Inner Circle revolves around the tensions that are bound to arise if a small group of people deliberately abandons the traditional moral values with which they were raised in favour of an unconventional outlook on love, marriage and sex.

While Kinsey preaches that sex is nothing but a "hormonal function" devoid of emotion, John Milk has extreme difficulty adjusting to this concept where his own wife — the young and beautiful Iris — is concerned.

Milk's sexual coming of age starts in 1939 when he is a student at Indiana University in Bloomington and attends Kinsey’s “marriage course”, a lecture in which the renowned zoologist propounds his theories and his plans for the first time in front of a large audience.