That Uncertain Feeling is a comic novel by Kingsley Amis, first published in 1955.
In 1962, the book was made into a film starring Peter Sellers, with the title changed to Only Two Can Play. It was also adapted by the BBC in 1985 as a television series, starring Denis Lawson and Sheila Gish, this time with the original title.
A satire on life and culture in a Welsh seaside town, the story concerns a married librarian who begins an affair with the bored wife of a local bigwig.