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"Mary of the 4th Form" is the second single by The Boomtown Rats. It was the first song taken from the band's first album The Boomtown Rats but the single is a different, re-recorded version from that on the album and 19 seconds longer. On French and Dutch releases of the single, "Do the Rat" (B-side of the UK version) was the A-side. The song's theme, of a teacher's sexual attraction to a pubescent girl, who behaves in an overtly sexual manner, was resonated in the Police song "Don't Stand So Close to Me".
"Mary of the 4th Form" peaked at No. 15 in the UK Singles Chart in 1977.