 Barrett's decline had a profound effect on Roger Waters' songwriting, and the theme of mental illness permeated Pink Floyd's later albums, particularly 1973's The Dark Side of the Moon and 1975's Wish You Were Here which was a deliberate and affectionate tribute to Barrett, the song, "Shine on You Crazy Diamond", and also 1979's The Wall. "Wish You Were Here", partly about Barrett, borrows imagery of a "steel rail" from Barrett's solo song, "If It's in You," from The Madcap Laughs album.
