“Encompassing heavy metal, folk, pure rock & roll, and blues, Led Zeppelin’s untitled fourth album is a monolithic record, defining not only Led Zeppelin but the sound and style of ’70s hard rock. Expanding on the breakthroughs of III, Zeppelin fuse their majestic hard rock with a mystical, rural English folk that gives the record an epic scope. Even at its most basic — the muscular, traditionalist “Rock and Roll” — the album has a grand sense of drama, which is only deepened by Robert Plant’s burgeoning obsession with mythology, religion, and the occult. Plant’s mysticism comes to a head on the eerie folk ballad “The Battle of Evermore,” a mandolin-driven song with haunting vocals from Sandy Denny, and on the epic “Stairway to Heaven.” Of all of Zeppelin’s songs, “Stairway to Heaven” is the most famous, and not unjustly. Building from a simple fingerpicked acoustic guitar to a storming torrent of guitar riffs and solos, it encapsulates the entire album in one song.” – All Music