“Chicano historiography has focused almost completely on heroes when describing the Mexican community,” Gonzales insists, “but most people, of whatever ethnic background, are not heroes, at least not most of the time.” Gonzales pointedly uses the phrase “Mexicans in the United States” rather than “Chicanos” because he regards “Chicanismo” as a movement rather than a field of scholarship. Gonzales (Indiana University Press: $29.95, 336 pages) allows us to glimpse a controversy that rages among scholars of Mexican American history and culture. The title of “Mexicanos: A History of Mexicans in the United States” by Manuel G. “Through graffiti,” she writes, “people who would otherwise never come into contact are forced into interaction-even if it is only the walls that speak.” What was once a mysterious and frightening scrawl on a garage door or a lamppost becomes something meaningful and compelling, if also deeply unsettling. Phillips succeeds in her stated goal of creating “a buffer of understanding” around graffiti-no one who reads “Wallbangin’ ” will look on street-corner graffiti in quite the same way again. She contrasts the graffiti of African American gangs and Chicano gangs-Chicano graffiti artists tend to use elaborate lettering styles, while African Americans favor “the mystical role of numbers.” She likens the graffiti that decorates our urban landscape to cave paintings and rock carvings found only in the wilderness-all of them can be seen as tribal markers that express secret meanings known only to insiders. She introduces us to the technical jargon of graffiti, explaining the differences among “tags,” “throw-ups,” “hit-ups,” “placas,” “strikes” and “pieces.” She distinguishes the boundary-marking tags of street gangs from the purely aesthetic efforts of “hip-hop” graffiti artists. Phillips acts as a guide and an interpreter for those of us who are utterly ignorant about the inner world of gangs and graffiti. Above all, Phillips is an acutely perceptive and deeply intuitive observer of Southern California’s urban scene, and she writes with urgency and clarity about a world that is otherwise barred to most of us. She can also be regarded as an art historian and a photo-documentarian, and at certain intimate moments, “Wallbangin’ ” is more nearly a memoir than a monograph. But her work is informed by something more than a scholarly interest in urban ethnography. Phillips is an anthropologist by training and profession, and “Wallbangin’ ” is based on her doctoral dissertation. “To look back on graffiti is to hear voices that otherwise would have remained silent.” “Graffiti allows people to create identity, share cultural values, redefine spaces, and manufacture inclusive or exclusive relationships,” Phillips explains. Yet the impulse to make a mark on the urban environment is so urgent and profound that it seems it simply cannot be suppressed-and the evidence can be found on walls and fences all over Southern California. Even the act of tagging a freeway sign requires a kind of acrobatic daring that can result in injury or death. Open warfare is likely to break out if one gang dares to cross out the graffiti of a rival gang. In 1995, a Sun Valley man, for example, shot two Latino teenagers when he came upon them as they were tagging an overpass. Phillips (University of Chicago Press, $25, 383 pages). But nowadays, tagging can be a matter of life or death, as we are reminded in “Wallbangin’: Graffiti and Gangs in L.A.” by Susan A. Graffiti can be found all over the world and in every period of history-some of the earliest examples were scratched into the pyramids of ancient Egypt by the nameless workers who built them.

Epic the tagger from san fernando