Blue Note 30363 (four CDs) .

Blue Note 30083 (four CDs), $57.98 . CODE: BAT-34

Here is some of the finest work of two brilliant jazz pianists. Powell was a protégé of Monk, and between them in the early 1940s the two defined bebop piano. Both were terrifically influential in their music and troubled in their lives; when their demons didn’t overwhelm them, they created astounding music. The Powell set begins with some of his first recording sessions as a leader, beginning in 1947. He’s at the top of his form as a bop virtuoso whose music seems to leave the keyboard and soar, and his range of styles is tremendous; he turns out a genuinely angry-sounding “Over the Rainbow” and a “Stella by Starlight” that almost sounds like Rachmaninoff. Some of the later recordings show him in decline, but there are always moments both thrilling and deeply moving, among them “Glass Enclosure,” an impassioned reflection from 1953 on a club manager’s confining him to his apartment to make sure he’d show up.

Monk recorded for more than a decade before getting the widespread recognition he deserved, and his Blue Note set is full of gems from those early years. The first sessions, in 1947 and 1948, already include classics like “Ruby, My Dear,” “Well You Needn’t,” and ” ‘Round Midnight,” played in that epigrammatic, knotty style, in which every off-balance note is perfectly, wryly placed. Milt Jackson joins him in a great 1951 session that includes a supreme marvel of abstraction, “Criss Cross.” The fourth CD is given over to a recently discovered amateur recording from Monk’s legendary 1958 engagement with John Coltrane at the Five Spot in New York. Both boxes include excellent liner notes by the jazz journalist Bob Blumenthal.