Conception is a jazz standard in the bebop style, written by George Shearing and noted for its chromatic descending chord sequences. It is in the key of D-flat. The original recording was made by the George Shearing Quintet in October 1949 and first issued on the single "East of the Sun (And West of the Moon)". Authorship is disputed: Al McKibbon, Buddy DeFranco, Gil Melle and Claude Williamson said Bud Powell composed some or all of it, as reported by Peter Pullman, while Lewis Porter argues that the tune is Shearing's.
In 1950 Miles Davis adapted the score, keeping Shearing's chord changes and main theme but replacing the bridge and ending. A February 1950 broadcast featured Davis with Stan Getz, J.J. Johnson and Art Blakey, and he recorded the arrangement in October 1951 for The New Sounds (Prestige, 1951). His 1950 nonet rewrite, "Deception", kept the new bridge and Shearing's progression, and his 1954 Blue Note "Take Off" uses the Conception progression with new material. Shearing's original was later recorded by Bud Powell and Kurt Rosenwinkel, and Davis's arrangement was often played by Chet Baker.
