Froth on the Daydream (French: L'Écume des jours; literally: "The Foam of Days") is a 1947 novel by the French author Boris Vian. Though told in a linear style, the novel concerns multiple plot lines, including the love stories of two couples, talking mice, and a man who ages years in a week. The novel uses a surrealist style. Though not the focus of the novel, one of these plot lines concerns a man who marries a woman who develops an illness that can only be treated by surrounding her with flowers. The book has been the basis for three feature films and an opera.