While EP + 6 is certainly an uneven compilation, it contains some of Mogwai's finest moments. Comprising non-album tracks pieced together by Chemikal Underground in the wake of their defection to Southpaw, it demonstrates that this truly revelatory avant-rock band has not only a grasp on the most astonishingly beautiful melodies, but also a keen understanding on how to warp them into vicious, masonry-cracking walls of noise in the blink of an eye. The very crystallisation of that approach is surely Mogwai's original recording of "Xmas Steps": from icy, stark bass drone to incendiary, dramatic math-rock fireworks to mournful violin lament in eleven heart-stopping minutes. Elsewhere, the material from Mogwai's 1999 EP easily ranks up there among the best things they've ever done: drifting epiphanies of noise that capture melancholy better than pretty much any band since Joy Division, and even rope in Cowdenbeath Brass Band for the graceful "Burn Girl Prom Queen". In such company, the early, ropily-recorded material from the 4 Satin EP seems disappointing--particularly, the soupy instrumental meltdown that drags "Stereodee" out to a tedious thirteen minutes, and rather suggests an indie band with ideas well above their station. Still, for any Mogwai fan that missed the original EP on its release, this should be considered crucial. -- Louis Pattison