The first five tracks are from "Hard Bop," a 1956 Columbia album (liner notes by Nat Hentoff), with a frontline of Jackie McClean on alto and the (under-recorded, under-appreciated) Bill Hardman, who played trumpet for Blakey in 3 different decades. It's some of the "hardest" hard bop you're likely to hear, raw and unforgiving, practically a league apart (in textures, dynamics, compositional interest--not necessarily in musicianship) from "Art Blakey and the Jazz Messengers" (with Mobley, Silver, Byrd), released on Columbia during the same year (not to be confused with the later Blue Note date that opens with Bobby Timmons' "Moanin'").
My copy is all in Japanese but appears to be a Sony reissue (now the owner of Columbia). The other selections are considerably "mellower," with a somewhat surprising (for Blakey and company) George Gershwin medley (which probably would not pass certain political correctness requirements these days). My only recording of the latter arrangement, which comprises the identical frontline as "Hard Bop," is from a session entitled "Tough!" on the Cadet label (a Chicago company associated with Argo Records). It's true that Blakey also made some impressive recordings with Johnny Griffin--not just on RCA but Bethlehem and Atlantic ("Hard Drive" and "Jazz Messengers with Thelonious Monk"), which have later shown up on Rhino, Savoy, and Collectables. In fact, the latter label offers both the albums "A Night in Tunisia" and "Jazz Messengers Play Lerner and Lowe" in a single 2-CD package (about the "Lerner and Lowe" album, the normally proud and competitive Hardman gives all the credit to Griffin, adding it was one of the most challenging sessions the Messengers ever recorded).
At least with this present Mosaic release of "Hard Bop" you can be assured of complete and accurate documentation.