For every taste and budget, a paperback

Bricks and Brownstone, by Charles Lockwood. New York: Abbeyville Press. 262 pp. $16.95.

The revitalization of old buildings is one of the most positive and exciting trends in America's cities today. Despite the gnawing fact of urban decline, thousands of distinguished but run-down inner-city houses, the brownstones, are being saved from destruction by people who care.As James Biddle, president of the National Trust for Historic Preservation, writes in the introduction: ''With the ongoing 'brownstone revival,' the quality of housing has improved dramatically in some neighborhoods.'' It's on the mend in such cities as Boston; Savannah, Ga.; Chicago; Richmond, Va.; Washington; Baltimore; and San Francisco.Information in the book provides valuable background on architectural styles, as well as documentation and guidance on the proper way to restore tarnished old buildings to their earlier glory.Mr. Lockwood knows whereof he writes. He owns a 100-year-old brownstone in Brooklyn, and he pays a lot of attention to detail.