The book follows two days in the life of Mathieu, a philosophy teacher, and his circle of friends as Mathieu tries to raise 4,000 francs to pay for an abortion for his mistress Marcelle. Mathieu's conscience tells him he should do the right thing and marry Marcelle but he doesn't wish to lose his freedom. To complicate matters Mathieu is in love with Ivich, a student who is awaiting her exam results. Mathieu goes around all his friends trying to borrow the 4,000 francs but none of them oblige. Thus we get great descriptions of café and bar life in Paris in 1938 as the second world war looms. It is Mathieu's brother who tries to force him to face up to ‘the age of reason' by declaring that he will give Mathieu 10,000 francs if he marries Marcelle. Brunet a friend tries to give his life direction by trying to persuade him to join the Communist Party. In the end he is forced to steal the money from the mistress of Ivich's brother Boris and his friend Daniel, a homosexual, actually gets married to Marcelle. Mathieu is left to reflect on his life of failure and declares that he has indeed reached the age of reason.
This report prepared by John Marcel