"I Know There's an Answer" (alternately known as "Hang On to Your Ego") is a song by American rock band the Beach Boys from their 1966 album Pet Sounds. Written by Brian Wilson, Terry Sachen, and Mike Love, the song was inspired by Wilson's experience with the drug LSD and his struggle with ego death. Musically, it is distinguished for its colorful arrangement, unorthodox structure, and bass harmonica solo. The instrumentation also includes guitars, tack piano, banjo, clarinets, flutes, electric keyboards, and timpani. Wilson, Love, and Al Jardine trade the lead vocal, for which the melody spans two octaves.