Procol Harum is a British rock band, formed in 1967, renowned for their fusion of rock with classical music elements. Their unique sound is characterized by Gary Brooker's powerful lead vocals and their use of the Hammond organ. The band gained international fame with their debut single, "A Whiter Shade of Pale," which is considered a classic in popular music history. Over time, Procol Harum's music has continued to influence the progressive rock genre, asserting their significance in the evolution of rock music.