The first instalment of a projected two-album set, Mezmerize sees System Of A Down, an American band of mostly Armenian heritage, further distilling their unique formula of thrash metal, socio-political rage, and Eastern European vocal melody into ever-more fiendishly complicated and white-knuckle exhilarating forms. Moreso even than 2001's Toxicity, this is a album of intense complexity: crammed with whiplash-inducing tempo-changes and a schizophrenic mood that sees sing-a-long, poppy choruses segued effortlessly into breakneck speed-metal, it's as bewildering on first listen as it is addictive after three. - Louis Pattison