Aleksandar Živojinović, known professionally as Alex Lifeson, is a Canadian musician, best known as the guitarist for the rock band Rush. In 1968, Lifeson co-founded a band that would later become Rush, with drummer John Rutsey and bassist and lead vocalist Jeff Jones. Jones was replaced by Geddy Lee a month later, and Rutsey was replaced by Neil Peart in 1974, after which the lineup remained unchanged until the band's dissolution in 2018. Lifeson was the only member of Rush who stayed in the band throughout its entire existence, and he and Lee were the only members to appear on all of the band's albums.

Rush was a Canadian rock band that primarily comprised Geddy Lee, Alex Lifeson (guitar) and Neil Peart. The band formed in Toronto in 1968 with Lifeson, drummer John Rutsey, and bass guitarist/vocalist Jeff Jones, whom Lee immediately replaced. After Lee joined, the band went through several line-up changes before arriving at its classic power trio line-up with the addition of Peart in July 1974, who replaced Rutsey four months after the release of their self-titled debut album; this line-up remained intact for the remainder of the band's career.