"The Moon's a Balloon" is an autobiography by British actor and comedian David Niven. Published in 1971, the book offers a humorous and candid look at Niven's life, from his childhood to his experiences in Hollywood. It captures the charm and wit that made him a beloved figure in the entertainment industry. The title refers to a line from a poem by William Blake, reflecting Niven's whimsical perspective on life. The memoir includes anecdotes about his friendships with other celebrities, such as Errol Flynn and Ava Gardner, providing readers with an engaging glimpse into the glamorous yet challenging world of show business.