Bebop! It's a rather silly word for a crucial chapter in jazz history. It didn't just come out of nowhere but evolved, fizzed and bubbled into existence in the USA in the early 1940s, as a result of a gloriously rich and complex musical chemistry involving different combinations of musicians, styles and places. All week, Donald Macleod and his special guest, the writer and broadcaster Geoffrey Smith, have some serious fun investigating this amazing musical phenomenon. To conclude the week they take a look beyond Bebop and explore the various shoots that have sprouted from the original stem, in the hands of such musicians as John Coltrane, Cecil Taylor, Miles Davis, Ornette Coleman, Eric Dolphy, Wynton Marsalis and finally Sonny Rollins, who brings us into the 21st century with his take on the Jerome Kern standard, 'Why Was I Born' - a live concert recording made in the immediate aftermath of 9/11.