A Hard Day's Night is a song by the English rock band the Beatles. Credited to Lennon -- McCartney, it was written by John Lennon, with some collaboration from Paul McCartney. It was released on the film soundtrack of the same name in 1964. It was also released in the UK as a single, with Things We Said Today as its B-side.\n\nAnswer this question: who wrote the song a hard day's night
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John Lennon , with some collaboration from Paul McCartney
This is the relevant information: Credited to Lennon -- McCartney, it was written by John Lennon, with some collaboration from Paul McCartney.

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The final answer: John Lennon , with some collaboration from Paul McCartney