The really important thing to know about H.P. Lovecraft is that he apparently inspired a Metallica song — watch and listen here, with full orchestral accompaniment.

UPDATE: Many emailers have noted the following:

In addition to Call of Ktulu, HPL also inspired the song “The Thing That Should Not Be”, on the Master of Puppets album. That one has lyrics.
Side note: The cover of Iron Maiden’s 1985 “Live After Death” album features the band’s undead mascot “Eddie” breaking out of his grave. His tombstone has the (attributed) quote “That is not dead /which can eternal lie / Yet with strange eons / even death may die…”