"I remember doing the backing track for 'Happiness Is a Warm Gun,' which took a long time. I remember they did over 100 takes of it, all the way through to two or three in the morning. Then they came back the next day and went all the way through again. But that wasn't unusual for them. I think George Martin had found an advertisement in a magazine that said 'Happiness is a warm gun,' because we were talking about it at the time. When the White Album was started, it was just when Robert Kennedy was shot. George Martin mentioned the ad to John, and shortly after the song came along."