Everyone's pretty sure that Tania is based on Anaïs Nin, Henry Miller's long-time mistress who also wrote the preface to Tropic of Cancer. How would you like to be one of the characters in a book like this?
Tropic of Cancer went all the way to the Supreme Court, folks. And it wasn't until 1964—a quarter of a century after it was first published—that it was finally deemed not obscene. Thank you, the 60s. (Source.)