Probably the two most interesting strands in American popular music since 1980 are hip-hop and hard-core punk. Both emerged organically from alienated subcultures and deployed a radical aesthetic purity.
Hip-hop has long had a literature, but hard-core punk is only beginning to be documented and placed in historical perspective. "American Hardcore" is an incredibly elaborate labor of love and is likely to be the definitive treatment of hard-core for the foreseeable future.
Hard-core is the vicious, extremely fast rhythmic noise that grew out of the work of original punk bands such as the Ramones and Sex Pistols. It encompasses everything from racist skinheads to left-wing anarchists, "straight-edge" ascetics and Hare Krishna thrash. Steven Blush of course gives accounts of the careers of the fundamental hard-core bands--Minor Threat, Black Flag and the Dead Kennedys, for example--and the fundamental scenes: L.A., Washington, D.C., and New York. But surprisingly he also manages to capture regional hard-core all over the country, and dozens or perhaps hundreds of bands, from Reno's 7 Seconds to Austin's Dicks.
Blush was a participant in the original hard-core world and was the road manager for the Washington, D.C., band No Trend. And though the book is constructed out of interviews with the people who were there in the early '80s, it is also highly personal and opinionated. This has made it controversial in the punk underground. But to my way of thinking, Blush's assessments of bands and situations is usually reasonable and acute. That Blush acts as a critic as well as a historian makes the book all the more entertaining.
The book leaves hard-core in the mid-'80s and basically asserts that the style died at that point, disintegrating into "emo" (emotional punk) and heavy metal. But hard-core punk is in the middle of a wildly cool revival. Maybe that's Blush's next encyclopedia.