Louis Armstrong was a prominent figure in American culture through his death in 1971, but many have argued that he was never as sharp as on the recordings he made in the late 1920s with the Hot Five and the Hot Seven. The newly compiled 10-CD set gathers the discs Armstrong recorded during the years when he was cutting edge, transmuting Dixieland and blues into music that prefigured swing and set the direction for jazz to come. Many of the recordings are loose and freewheeling, often improvised in the studio from ideas Armstrong and his bands had played with on countless nightclub gigs. All of it is infused with his unmistakable joyful soul.