As bop piano goes, Thelonious Monk had the ideas and tunes, but Bud Powell had the chops. More than anyone, he created bebop piano, influencing everyone who came after, partly by adapting saxophonist Charlie Parker's mercurial wit, speed and timing to the keyboard. (Hear Parker's "Ornithology.") His right hand melodies dart and zag like Bird, but his left was another story. Pre-bop, most pianists kept a regular rhythm going in the bass. Bud's southpaw rapped out terse punctuations, for a leaner, looser approach that became second nature to jazz pianists. (His elliptical friend Monk was likely one inspiration there, and on Bud's advanced harmonies.) Powell's lines sing, and he wrote fleet, nifty tunes: "Un Poco Loco," "Parisian Thoroughfare." Psychological problems marred much of his later work, but these early sides for trio (with Roy Haynes or Max Roach on drums) and quintet (adding trumpet spitfire Fats Navarro and young tenor Sonny Rollins) are essential listening.