Photo: n/aSoul the genre still but a faint blip on America’s post-war rock radar, Sam Cooke came finger-snapping in on this day in 1957 and dropped a crossover bomb on the R&B charts. Or maybe a glimmering revolver is a better analogy, as “You Send Me” was a smooth threat to its contemporaries, too sexy to be gospel, yet too chill to own a backbeat, Cooke wooing his crystalline yearn all the while. “Now I find myself wanting/To marry you and take you home,” the 26-year-old star repeats in the chorus. A set of choir girls underscore the glow. And pop balladry would never be the same.