The current members of Rush (Alex Lifeson, Neil Peart, Geddy Lee) have been together for so long it's easy to forget that it is not the original lineup.
In the beginning (1968) John Rutsey was Rush's drummer, appearing on the band's first single and album. He left the band shortly after the debut album was released in 1974, because he was diabetic and was concerned about the affect of long tours on his health. In fact, when he left Rush, he left the music business altogether.
Rutsey died in his sleep on Sunday (May 11) apparently of a heart attack that was the result of his diabetes. He was 55.