Harold Eugene Clark was an American singer-songwriter and founding member of the folk rock band the Byrds. He was the Byrds' principal songwriter between 1964 and early 1966, writing most of the band's best-known originals from this period, including "I'll Feel a Whole Lot Better", "She Don't Care About Time", "Eight Miles High" and "Set You Free This Time". Although he did not achieve commercial success as a solo artist, Clark was in the vanguard of popular music during much of his career, prefiguring developments in such disparate subgenres as psychedelic rock, baroque pop, newgrass, country rock, and alternative country. He was inducted into the Rock and Roll Hall of Fame in 1991 as a member of the Byrds.

"Eight Miles High" is a song by the American rock band the Byrds, written by Gene Clark, Jim McGuinn, and David Crosby. It was first released as a single on March 14, 1966. Musically influenced by sitar player Ravi Shankar and jazz saxophonist John Coltrane, the song was influential in developing the musical styles of psychedelia and raga rock. Accordingly, critics often cite "Eight Miles High" as being the first bona fide psychedelic rock song, as well as a classic of the counterculture era.