Writer and former graffiti tagger Roger Gastman has turned his love of the spray arts into a lifelong career. At 19, he sold graffiti supplies, later founded a boutique media agency that specializes in street culture, and as a 33-year-old, co-authored "The History of American Graffiti" with graffiti artist Caleb Neelon. The book chronicles the history of graffiti in more than 25 cities. Most recently, Gastman co-curated an exhibition at the Los Angeles Museum of Contemporary Art (MoCA) entitled "Art in the Streets." It's the first major U.S. museum survey of graffiti and street art. Speakeasy spoke with Gastman about graffiti as art and his book.