- John Maynard Keynes, a famous British economist, kept two coded sex diaries from 1901-1915 documenting his sexual encounters and activities.

- The first diary lists his partners by initials or nicknames on a year-by-year basis, including details like "16-year-old under Etna."

- The second diary is also organized yearly but breaks it into quarters, coding his activities into categories C, A, and W, and tallying the numbers of times each occurred.

- Most associate A with "ass" and W with "wanking" but the meanings and C are less clear based on the frequency and numbers involved.

- C could refer to more general acts like "copping" (kissing, fondling), "cruising," or "cottaging" (seeking sex in public bathrooms), which were common at the time.

- The high numbers for C correlate with university breaks, suggesting more opportunities for anonymous encounters.

- Additional numbers attached to each quarter may be Keynes grading his own performance on a scale from 65-100.

- Keynes was actively pursuing both economic and sexual markets in his personal life.

- The diaries provide a unique historical window into same-sex relations and coded language of the early 20th century in Britain.

- Debate continues around fully decoding the meaning of Keynes' cryptic sex diary categories and numbers.