Of all the amazing music Al Green made in the 1970s—a run that included singles like “Let’s Stay Together,” “Love and Happiness,” and “Take Me to the River”—nothing in his discography is as complete, nor as complex, as Call Me. By the time of the album’s release in 1973, Green had already proved that soul didn’t have to be effusive to be devastating, and that the true measure of a man’s strength isn’t his power, but his vulnerability and restraint. Some suitors wanted to have you, but Al Green wanted to please you—a quality of devotion that turned conventional gender dynamics inside out, and made his later turn toward Christianity all the more resonant: Even his love songs are worship songs. Call Me isn’t a radical shift so much as it is an enrichment. Green doesn’t just flirt with gospel, he sermonizes (“Jesus Is Waiting”); he doesn’t just embrace his Southernness, he complicates it by pointing out how country and soul come from the same well (“I’m So Lonesome I Could Cry,” “Funny How Time Slips Away”). That adventurousness might explain how Call Me became not only one of Green’s most critically acclaimed efforts, but one of his most commercially successful. Green once said he preferred recording when he was tired, because then he wouldn’t have the wherewithal to hold back how he really felt. It’s a strange image, in a way: The affable, family-friendly showman indulging in personal mysticism to unlock his hidden side. But it also speaks to the supernatural quality in Green’s music that reverberates through Prince, D’Angelo, Erykah Badu, Frank Ocean, and any other artist who’s used the earthiness of everyday experience to discover portals into the unknown. Green’s music is soul, yes—but also seance. “I believe there’s gonna be an explosion,” he sings on “Here I Am (Come and Take Me).” The fountain of whimpers and half-words that comes next isn’t what he promises—it’s quieter, stranger, and less direct. And while you might not know what he’s saying, he makes clear how he feels.