RIAA's "Grammy Award Winners For Best Rock Album"
The first rock Grammy categories appeared in 1979 (Donna Summer won one?!?) but it wasn’t until 1995 that they had an overall "Best Rock Album" category. Prior to that the Grammys were very inconsistent, awarding best male, female, duo…sometimes just for a song, sometimes the whole album. Also, you could argue that the "Best Contemporary Album" functioned as the rock Grammy for several years. (For example, the 1967 winner was the Beatles "SGT. PEPPER’S LONELYHEARTSCLUBBAND".)