Having already asserted their dominance on their first two hard rocking, raunchy records, Led Zeppelin takes a step back on their third outing to flex their compositional chops.

And that means a surprising amount of ballads.

There are plenty of headbangers on this disk—the record opens with “Immigrant Song,” for crying out loud. But this is the first Led Zeppelin disk to feature much acoustic guitar at all.

The second track, “Friends,” is driven by a bluesy acoustic riff and an Eastern-tinged orchestra. If anyone had written them off as a bunch of tuneless, high-voltage noise-makers, this track sets the record straight. “Bon-Y-Aur Stomp” could have been a Mumford & Sons tune if it was written forty years later (and if it wasn’t as good).

Don’t think that Led Zeppelin is getting soft, though. They still know how to rock. “Celebration Day” and “Out on the Tiles” are just as raucous and fiery as the deep cuts on the first two albums. “Tangerine” seems to be a breezy pop tune with one of the most charming choruses they’ve ever written…before it launches into a minor key guitar solo.

But in my opinion, the forgotten standout is “Since I’ve Been Loving You.” The song is a blues epic for the ages. Robert Plant’s wailing tenor and Jimmy Page’s shrieking guitar leads dance in the upper registers while John Paul and John conjure thunder down below, all while subtle organs give a lush atmosphere.

Led Zeppelin III is most certainly a transitionary album, seated nicely between the sonic anarchy of the first two albums and the intricately composed epics and pop sensibilities of their later records.

And while that might have underwhelmed critics in 1970, it’s found the acclaim it deserves in later days. In fact, it might actually be my favorite. It stands on its own feet without the context of the albums around it. A truly great record by a truly great band.