Thelonious Sphere Monk (/θəˈloʊniəs/, October 10, 1917 – February 17, 1982) was an American jazz pianist and composer. He had a unique improvisational style and made numerous contributions to the standard jazz repertoire, including “‘Round Midnight“, “Blue Monk“, “Straight, No Chaser“, “Ruby, My Dear“, “In Walked Bud“, and “Well, You Needn’t“. Monk is the second-most-recorded jazz composer after Duke Ellington, which is particularly remarkable as Ellington composed more than a thousand pieces, whereas Monk wrote about 70.

Monk’s compositions and improvisations feature dissonances and angular melodic twists and are consistent with his unorthodox approach to the piano, which combined a highly percussive attack with abrupt, dramatic use of switched key releases, silences, and hesitations. His style was not universally appreciated; the poet and jazz critic Philip Larkin dismissed him as “the elephant on the keyboard”.

Monk was renowned for a distinct look which included suits, hats, and sunglasses. He was also noted for an idiosyncratic habit during performances: while other musicians continued playing, Monk stopped, stood up, and danced for a few moments before returning to the piano.

Monk is one of five jazz musicians to have been featured on the cover of Time magazine (the others being Louis Armstrong, Dave Brubeck, Duke Ellington and Wynton Marsalis). Thelonious Sphere Monk was born two years after his sister Marion on October 10, 1917, in Rocky Mount, North Carolina, and was the son of Thelonious and Barbara Monk. His poorly written birth certificate misspelled his first name as “Thelious” or “Thelius”. It also did not list his middle name, taken from his maternal grandfather, Sphere Batts.

“Monk’s usual piano touch was harsh and percussive, even in ballads. He often attacked the keyboard anew for each note, rather than striving for any semblance of legato. Often seemingly unintentional seconds embellish his melodic lines, giving the effect of someone playing while wearing work gloves. […] He hit the keys with fingers held flat rather than in a natural curve, and held his free fingers high above the keys. […] Sometimes he hit a single key with more than one finger, and divided single-line melodies between the two hands.” In contrast with this unorthodox approach to playing, he could play runs and arpeggios with great speed and accuracy. He also had good finger independence, allowing him to play a melodic line and a trill simultaneously in his right hand.

Monk often used parts of whole tone scales, played either ascending or descending, and covering several octaves. He also had extended improvisations that featured parallel sixths (he also used these in the themes of some of his compositions). His solos also feature space and long notes. Unusually for a bebop-based pianist, as an accompanist and on solo performances he often employed a left-hand stride pattern. A further characteristic of his work as an accompanist was his tendency to stop playing, leaving a soloist with just bass and drums for support.

Monk had a particular proclivity for the key of B flat. All of his many blues compositions, including “Blue Monk,” “Misterioso,” “Blues Five Spot,” and “Functional,” were composed in B flat; in addition, his signature theme, “Thelonious,” largely consists of an insistently repeated B-flat tone.