Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Crust punk is a form of music influenced by anarcho-punk, hardcore punk and extreme metal. The style, which evolved in the mid-1980s in England, often has songs with dark and pessimistic lyrics that linger on political and social ills. Crust is partly defined by its bassy" and "dirty" sound. It is often played at a fast tempo with occasional slow sections. Vocals are usually guttural and may be growled or screamed. Crust punk takes cues from the anarcho-punk of Crass and Discharge, the extreme metal of bands like Venom and Celtic Frost and, in some of its more dissonant strains, subtle elements of post-punk via Killing Joke. Crust punk has always remained a deeply underground form of music, although fans of the style are found worldwide. The early work of Doom, Amebix, Nausea, Antisect, and Hellbastard constitute prototypical crust punk. "