This entry from Encyclopedia Britannica features Horace Silver, an American jazz pianist, composer, and bandleader, exemplary performer of what came to be called the hard bop style of the 1950s and '60s. The style was an extension of bebop, with elements of rhythm and blues, gospel, and Latin-American music added. The style was marked by increased interest in composing original tunes with unusual structures, in place of the bebop practice of loosely basing improvisations on the chord progressions of a few favourite pop tunes such as "I Got Rhythm," "Indiana," and "What Is This Thing Called Love?".