The Gnawa are Moroccans, descendents of slaves who were among the earliest disciples of Islam. To this day they see themselves as a societal underclass, and over centuries, a highly percussive, repetitive music has grown around their ceremonial rituals and dances. A Louisville label helped bring out this CD/DVD overview of the music, with fairly detailed liner notes that help toward interpretation. Thank goodness for the DVD: The point of some of the musical passages here is to develop a dialogue between the lead instrumentalist (playing a 3-string lute called a guinbri) and dancers who may feel under the influence of mystical figures, so it’s important to have a visual component. The chants and limited (but spirited) percussion can add a lot to a performance, but some of the guinbri masters have rockstar chops, slyly displayed like a great blues guitarist wailing on a spiritual at a small revival meeting. Without such moments, this album’s just for cultural historians.