"Happy Jack" was one of the Who's most lighthearted singles, reaching number three in the U.K. after its release in late 1966, and providing their belated commercial breakthrough in the United States, where it reached the Top 30 in mid-1967. "Happy Jack" is grounded in two musical hooks: a jaunty, playful, circular guitar riff, and an insistent two-note bass line that pulses through much of the track. Like much of composer Pete Townshends work from the period (indeed much work by major British groups the Beatles and the Kinks in 1966-1967), it has a chipper, singalong feel. Further parallels with the Beatles and the Kinks in 1966-1967? It's a whimsical third-person character sketch of a strange fellow named "Happy Jack" who lives on the Isle of Man and stays happy in spite of abuse from the local kids. (Sometimes it's been said that "Happy Jack" is about a donkey, but in fact the song does state at its outset that Happy Jack is a man.) The irregular, nervous tempo of the verses gives way to a brief bridge with a brasher, more upbeat rhythm and chords before returning to the main motif. The Beach Boys' influence upon the Who, in their harmonies mostly, reached a peak in 1966 and 1967, and "Happy Jack" is one of the tracks in which that trait is most apparent, especially in the high harmonies on the bridge. The cleverest part of the arrangement, in fact, is probably the varied harmonies on the verse, in which the group shoots off rapid-fir, stuttering "la-la"s. Considered one of their more lightweight efforts by some critics, "Happy Jack" was nonetheless highly enjoyable and gave them an all-important entree into the U.S. market, after a couple of fruitless years that had seen almost half a dozen excellent previous singles ignored. The famous tag -- Pete Townshend faintly saying "I saw ya" -- occurred when Keith Moon was making funny faces at the group while the harmonies were recorded. Told to lie on the floor out of sight, he popped his head above the glass partition separating him from the rest of the group at the very end of a take, prompting Townshend's remark -- little noted by listeners at the time, but eventually a well-known piece of Who lore.