Led by the brilliant Curtis Mayfield, the Impressions spear-headed the transformation of doo-wop into Soul music. Mayfield looked to the smooth strains of Gospel music rather than to other street corner vocal groups and wrote deceptively simple, stripped-down arrangements on such classics as "It's All Right." Always an elegant, harmony-rich outfit, the Impressions started referencing the civil rights struggle on such hits as "People Get Ready" and "This is My Country" without ever getting heavy-handed or forgetting about crafting great songs. Mayfield became an R&B mover and shaker, writing and producing for other acts before going on to an impressive solo career in 1970. The Impressions carried on without their leader after 1970 and their later work, while not groundbreaking, remained top-shelf Soul. The Impressions left an R&B legacy equal to that of Ray Charles, Sam Cooke, Marvin Gaye or Stevie Wonder.