So much has been said about Louis Armstrong's groundbreaking recordings with his Hot Five and Hot Seven ensembles that to add more is to risk overstating the obvious. Suffice it to say that this four-disc box set, which collects all the recordings Armstrong made with both groups between 1925 and 1929, is of inestimable historical and musical importance. Everything about the music, from the taut, sassy interplay of the musicians, to Satchmo's dazzling chops on the cornet, to his extemporaneous scatting (the first recorded instance of what would become a jazz technique), is a revelation. The contents of the set, in structure and in spirit, is the nucleus of the entire jazz movement, and the sumptuous packaging, excellent sound, and detailed notes make it a cornerstone for any self-respecting music collection.