From topping the charts to epic pieces taking up a side of vinyl, and even both at the same time, YES are among of the longest lasting and the most successful of the ’70s progressive rock groups, proving to be one of the lasting success stories from that musical genre. The band, founded in 1968, overcame a generational shift in its audience and the departure of its most visible members at key points in its history to reach the end of the century as the definitive progressive rock band.