Procol Harum didn't make the cut.
From Rolling Stone.com:
The Rock and Roll Hall of Fame has officially announced next year's inductees: Rush, Public Enemy, Heart, Randy Newman, Donna Summer and Albert King will all join the class of 2013, with Summer, who passed away this May, and King, who died in 1992, earning the honor posthumously. Lou Adler and Quincy Jones will both receive the Ahmet Ertegun Award for non-performers.
I will console myself, as I often do, by listening to perhaps my favorite track from their masterpiece A Salty Dog -- Matthew Fisher's beyond gorgeous "Pilgrim's Progress."
Incidentally, the short concluding section of this one -- which starts at 3:11 seconds in -- has roughly the same relevance to the body of the song as the non-vocal ending section of "Layla" has to the rest of that record.
And, IMHO, it's the single best instrumental in rock history.
I am not kidding about this.
I should add that until today I had no idea this had ever been released as a single anywhere.