Billy Harrison is a Northern Irish musician, best known as the lead guitarist of the band Them, which was formed in 1964. The group is celebrated for its contribution to the garage rock and proto-punk genres, with a distinctive sound characterized by bluesy rock and R&B influences. Harrison's work with Them includes notable tracks like “Gloria,” a song that has since become a rock classic and has been covered by numerous artists, including Van Morrison, who was the band's original lead singer. Harrison's guitar work and songwriting played a crucial role in shaping the band's sound, contributing to the raw energy that characterized much of the music coming out of the 1960s British rock scene. After leaving Them, Harrison pursued various musical projects, including working with other bands and solo endeavors, but he is most prominently recognized for his time with Them. The impact of Harrison and Them is significant, as they helped lay the groundwork for the garage rock revival and influenced later punk and rock musicians. Their music remains influential, and “Gloria” is often cited as one of the foundational songs of rock music.