A fascinating cross-section of a subculture many people might not be aware of: DJ'ing and "turntablism." The documentary does a perfect job of interspersing interviews with DJ'ing legends, all while putting a hip-hop soundtrack behind it. It both tells AND shows the history of scratch DJ'ing.
Scratch examines the philosophy of DJ'ing, in addition to the art itself. It explores technique, innovations, styles. It's incredible how diverse the DJ community is, with battlers, beat-jugglers, party-rockers, avant-garde DJs, showmen, and experimentalists.
The DJ community also appears to be incredibly supportive, with no beef between the crate-diggers and the heavy-scratch DJs. It's a grassroots approach: everyone was influenced (either directly or indirectly) by Herbie Hancock's "Rockit," no one is famous outside hip hoppers.
The racial and stylistic diversity is a celebration (one might call it a lionization) of this subculture. And the skill with which the players scratch records continues to amaze me.