Since its appearance on the music scene in 2003, The Bad Plus has been at the forefront of numerous debates within the world of jazz and beyond. Questions of genre placement and definition terminology seem to plague this esoteric band. Its newest disc Prog certainly won't answer these questions or solve these debates. In fact, it might just spur these arguments on. However, there is a solid truth to be found regardless: these three musicians—Reid Anderson (bass), Ethan Iverson (piano) and David King (drums)—make serious, ground-shaking music that is not to be overlooked.

Prog is a rather eccentric hodgepodge of rock covers and unconventional originals. Ranging from such artists as Tears for Fears to the progressive rock group Rush, this assortment of melodies parades a diversity in style that has come to be expected of the edgy trio. Melodic and contemplative at one moment, the next might bombard with head banging antics. The covers on the album are approached with artistic integrity and originality, as beautifully shown on the Rush tune "Tom Sawyer. Iverson's melodic phrasing and harmonic approach present a perfect blend of juxtaposition and cooperation between the rhythm section and the lead player.

The erratic "Physical Cities is one of the originals that captures the vibe of the album in one singular track. Starting with a driving, somewhat groovy bass line, the group weaves in and out of what are predominantly jazz solos over rockish melodies and grooves. The tune ends, somewhat abstractly, on a hard-hitting atonal repetition of notes that leaves the melody somewhat open ended.

Prog is a modernistic approach to the music of jazz. The Bad Plus has made its name on just such a reputation and the result is an extremely pleasing concoction of music that leaves the listener deep in thought.