ETHNIC L.A.<i> by Zena Pearlstone (Hillcrest Press, P.O. Box 10636, Beverly Hills, Calif. 90210: $12.95; 188 pp.) </i>

Los Angeles is the second-largest Mexican, Armenian, Korean, Filipino, Salvadoran and Guatemalan city in the world, and more than 50 foreign-language newspapers are published in L.A. County, says Zena Pearlstone in “Ethnic L.A.” Her book describes the enormous human diversity of the city, to which the author applies the metaphor mosaic rather than melting pot, because the communities tend to retain their individual characters. With its statistics and local histories of the various ethnic groups, this book can be used as a reference, or it can function as a guidebook: It concludes with lists of ethnic foods, religious centers and a calendar of celebrations that could keep any tourist occupied every day of the year.