Travels With My Aunt - Graham Greene
The theme of an uptight man becoming liberated through a relationship with an unconventional and unrestrained woman is hardly unusual (cf just about every Woody Allen movie) but the twist here is that the woman is not a sexually available youngster but an elderly aunt. Hijinks ensue to reasonably entertaining and beautifully written effect, but some of the social attitudes are a little embarrassing for something published in 1969.
A minor Greene, to be sure, but not without it's pleasures.