(FORTUNE Magazine) – "I Shall Be Released," by Elvis Presley Available in the boxed set Walk a Mile in My Shoes--The Essential '70s Masters (RCA)

At 48 seconds, this is surely the shortest musical masterpiece since Charlie Parker's 47-second "Famous Alto Break" from 1946. But it's the very shortness that makes Elvis' version of Bob Dylan's "I Shall Be Released" so searing. For a brief moment he opens a door and stands unguarded. Then, in the final seconds, he slams the door shut. It's the rock equivalent of Rembrandt's Aristotle Contemplating the Bust of Homer: the philosopher (Elvis), draped in the rich robes and golden chains he'd earned tutoring in a royal court, staring mournfully at the plain bust of the still uncompromised poet (Dylan).

The tape was made during some odd moment in a studio in 1971. "I see my light," Elvis begins but in the wrong key. He immediately drops down and continues through the short chorus. There's noise in the background, people talking. Elvis' singing is beautiful and unaffected, but he's not just tossing the song off. You can sense his concentration and, despite the relaxed atmosphere, a tension. He's saying something here. He finishes the chorus and then says, "Dylan." In those two syllables is Elvis' stern, unblinking, final judgment--not of Dylan, but of himself.

--GREGORY CURTIS