Sonny Rollins Plus 4 was recorded on March 22, 1956 at Capitol Studios in Los Angeles and released on Prestige Records. The "Plus 4" refers to the Clifford Brown-Max Roach Quintet — trumpeter Brown, drummer Roach, pianist Richie Powell, and bassist George Morrow — who served as the backing group. The five-track program includes Rollins originals like "Pent-Up House," which became one of his signature compositions, alongside "Valse Hot" and "Kiss and Run," plus the standards "Count Your Blessings (Instead of Sheep)" and "I Feel a Song Coming On." The session captures two of the most distinctive voices in 1950s jazz — Rollins's thick, rhythmically inventive tenor and Brown's brilliant, lyrical trumpet — in a quintet setting that maximizes the contrast between their styles. Tragically, Brown and Powell died in a car accident less than four months after this recording, on June 26, 1956, making this one of the last studio sessions to feature Brown's trumpet. "Pent-Up House" opens with an infectious, riff-based melody that has remained a jam session staple, while Rollins's interpretation of "I Feel a Song Coming On" demonstrates his gift for melodic paraphrase. The album is a significant document of two major jazz artists at the peak of their creative powers.