Book excerpt: For its initiates, jazz is instinctive and engaging the way that popular music should be. For non-aficionados, it can be slippery and difficult to grasp: without familiar forms or a hard-and-fast format, and largely ruled by improvisation, jazz leaves the novice baffled, not sure how to listen, and asking how is it that they know what to play? 30-Second Jazz explains, in easy, short riffs that keep you engaged, taking readers from the African-American roots of jazz all the way to todays global mix of musicians and styles. Along the way, it looks at the shape, style, and instruments of jazz, at key personalities and recordings in the jazz canon and at what might be expected next from this most diverse of musical forms.