"The Diary" is a song by Neil Sedaka and Howard Greenfield.
[1] This song's writers, Sedaka and Howard Greenfield, were inspired to write the song after asking for (and being refused) access to their client Connie Francis's diary in hopes of mining it for lyrical material.
(It had a very similar sound to that group's first hit, "Tears on My Pillow".)
[3] The Imperials' version didn't chart, so Sedaka took it and decided that he should record the song himself.
It was reissued on his 1961 record Neil Sedaka Sings Little Devil and His Other Hits, and again in 1963 on the album Neil Sedaka Sings His Greatest Hits.