Journalist Dolan's first book describes the development and significance of this durable American symbol of "small-r republican, small-d democratic openness." It turns out that the porch has a diverse lineage, with roots in Mediterranean Europe, West Africa, the Caribbean and India, and a bewildering variety of terms for ancestral or related structures. Indeed, the subject may be too diffuse and elusive for Dolan's approach—an intermediary space between interior and exterior appears to be such a basic element of tropical architecture that one could as easily write a history of the window or the door. It takes a while for Dolan to warm up to his subject, and the early chapters are studded with uneasy speculation and irrelevant byways. Dolan is on surer ground once he reaches the United States—his anecdotes cohere into a narrative, and his analysis of the significance of the porch is more persuasive. Dolan amply demonstrates that the porch is primarily a means of escaping the heat and, almost as important, a locus for casual social interaction. The 19th century was the Golden Age of the American Porch. As Dolan glumly notes, the disappearance of the outhouse and the advent of the automobile were among the factors that caused the front porch to fall into disfavor, almost to complete extinction, during the suburban 20th century. The good news for Dolan and his confreres is that the porch is making an unanticipated comeback. B&w illus.; 32 pages color illus. not seen by PW. (Nov.)