An extension of the hard-bop movement of the '50s, soul jazz injected a strong dose of gospel and R&B into the form, accenting swing grooves with funky head-nodding rhythms and melodic forms with bluesy call-and-response. The sound is built from strong, cycling bass lines inextricably linked to beats that swing, shuffle, or stutter. By the early '60s bandleaders like Horace Silver and Lee Morgan introduced tunes with relentlessly driving, funky cadences and shimmying horn patterns, the latter scoring a smash hit and creating a virtual paradigm with “The Sidewinder.” The format’s popularity grew with the ascent of organ trios led by Jimmy Smith and Baby Face Willette, smashing together the sacred and profane à la Ray Charles. Soul jazz retained sublime technique and improvisational brio, yet by rooting its expression in dance-like forms it connected to a larger audience, its earthy ebullience explaining its ongoing popularity, with the Hammond B-3 organ maintaining primacy decades later.