Termed in the subtitle an ""Anatomy of Poverty,"" this compassionate study of ""the poorest spot in the richest city in the world"" is an important book, although the reader may wish that the author's dual purpose -- to be ""both descriptive and prescriptive"" -- had been oftener served by her strong personal feelings toward her subject than by the cautious generalities to which her profession sometimes makes her prone. Professor of Sociology at NYU, Dr. Sexton intended to spend two weeks in Spanish Harlem, but stayed instead for nearly two years, drawn by what she calls ""an unusual intensity of being."" Her investigations led her into intimate identification with the problems of unemployment, substandard housing and schools, delinquency, drug addiction, and the lack of effective community relations. The possible cures she tenders are hardly new, but she presents them with urgency and sincere hopefulness. The aim would be to give the poor a sense that they are able, ""through their own initiative"" and ""solidarity with others, to organize to alter successfully their environment."" Her specific proposals to this end are admittedly tentative, but, granted the readership deserved, they could very well serve for the first real push toward real solutions.