Horricks packs a lot into this little book, which is part of the Jazz Masters series issued in the UK in the early 1980s. He does a good job of summarizing Gillespie's contributions to jazz and placing them in historical context. If I have a quibble, it's that Horricks makes too much of bebop (the modern jazz style Gillespie helped introduce) being revolutionary. I see it more as an evolutionary step, not the drastic break from the past the Horricks describes.