*** FAITHLESS, “Outrospective,”<i> Arista</i>

This English outfit has had its share of successes in the club world, but the group seemed destined to be most famous as the launching pad for Dido. The pop star’s brother, Rollo Armstrong, is the group’s mastermind, and she got her start singing with the band.

No more. Dido turns in a cameo appearance here, playing the ethereal chanteuse to perfection on the haunting “One Step Too Far,” but “Outrospective” can rest entirely on its own considerable merits.

A superb collection of genre-crossing grooves, “Outrospective” is a remarkable progression for the group, which is still governed by Armstrong and fronted by Lady Bliss and Maxi Jazz.

The intricate beats of the dance-meets-world “Tarantula” are unlike anything on the previous two Faithless efforts. Likewise “Muhammad Ali,” which moves seamlessly from trip-hop verses into a silky smooth soul chorus. The revelations of “Outrospective” are seemingly nonstop, including the purely tribal “Machines R Us” and the warbling ballad “Not Enuff Love.”

As impressive as the record’s diversity is its ability to evoke moods both light and dark within seconds of each other. “Outrospective” fully comprehends the power of beats, and uses that knowledge brilliantly.

*

Albums are rated on a scale of one star (poor), two stars (fair), three stars (good) and four stars (excellent). The albums are already released unless otherwise noted.