After the frantic Bebop pace set by Charlie Parker, Dizzy Gillespie and others in the late 40s, a new school of Jazz began to develop. Hard Bop heavyweights such as Sonny Rollins and Horace Silver slowed down the pace a bit with more deliberate melodic lines set against the built upon the framework of the Bebop revolution. Bebop will take you to another dimension, Hard Bop will drive you home. --redjazzradio
