The quartet Cal Tjader kept together during 1956 and 1957 was devoted to straight-ahead jazz. Tjader's Latin fans may have missed his celebrated ritmos calientes, but they found ample consolation in enjoyment of one of the most swinging groups the popular vibraharpist ever led. Tjader, pianist Vince Guaraldi, drummer Al Torre, and bassist Gene Wright (in his pre-Brubeck days) loved playing together. Their mutual joy was visible and audible. It was captured at the Black Hawk, Tjader's San Francisco headquarters, on an occasion when the band had an audience that felt the vibes, so to speak, and inspired the musicians to an exceptional level. The late Ralph J. Gleason's liner notes caught not only the spirit of the music, but some of the character (and characters) of the beloved Black Hawk.