Complex sentence: In the summer of 1968, Lifeson founded the band that would become Rush with friend and drummer John Rutsey, and bassist/lead vocalist Jeff Jones, who would be replaced by current front man Geddy Lee a month later.
Split into simpler sentences: In the summer of 1968, Lifeson co-founded the band that would become Rush. Other co-founders are friend and drummer John Rutsey, bassist and lead vocalist Jeff Jones, and Jones's successor, current front man Geddy Lee a month later.