Once upon a time, bootleg albums - privately made recordings, usually of concerts made w/out the artists’ and/or "official" record companies’ knowledge or approval - were called airchecks, because the source of the material was often radio broadcasts from clubs or concerts. Some bootlegs attain legendary status, and some eventually get released officially - this, as you’ve by now gathered, is one such. Birdland 1951 collects three different Miles shows from that year with two sextets, the lineup of each a who’s-who of the first wave of bebop and some hepcats who continue (to this day) to impact jazz and beyond (Miles of course, Mingus, Blakey, Rollins). Sure, the recording quality isn’t, to be frank, great - it does sound like it’s emanating from an old, cheap, non-stereo radio (& you’ll prob’ly need to crank up the "bass" dial - but this platter IS still quite listenable once you "accept" the limitations of the source, and musically it’s the s**t. Though Miles had given Birth to the Cool only a year or so before, here he is BLAZING hot (with his cool-cat mid-register sound) through these bebop originals. J.J. Johnson roars, all brash, blues-charged ‘n’ punchy, a trombonely incarnation of Charlie Parker. Sonny Rollins’ signature sound - that steely shiny tone of his late 50 & 60s peak - is in embryo here (still under the sway of Parker and Dexter Gordon) but he plays with a riveting, gale-force intensity that’s a wonder to behold. (Especially since - horror of horrors - I’m not the biggest fan of Rollins in general. Hold your hate mail - while I appreciate his tremendous technique and influence, he just doesn't move me as much as, say, Johnny Griffin, Stan Getz or Jimmy Heath.) Everyone here plays at the top of their game, with good-natured edge and wit, and as if under the influence of a triple shot (at least) of espresso (or some muy caliente Mexican chow). While not recommended for the casual Miles fan, but for the hardcore devotee (and that of the late 1940s/early 50s bebop epoch), this is, to coin a weary cliché, a Major Find.