What style of jazz was the most popular?

Bebop was the most popular style of jazz in the 1940s. It was characterized by fast tempos, complex harmonies, and intricate melodies. Bebop was a significant departure from the traditional swing style of jazz and was considered to be more challenging to play and listen to. Some of the most famous bebop musicians included Charlie Parker, Dizzy Gillespie, Thelonious Monk, and Bud Powell. Bebop was the first style of jazz to be considered "modern jazz," and it paved the way for the development of other modern jazz styles, such as hard bop, cool jazz, and free jazz.