JUDITH FINGARD paints The Dark Side of Life in Victorian Halifax (Pottersfield, 224 pages, $16.95 paper) in all its ugliness, yet the book's cheerful tone seems to echo the author's delight in finely sifted scholarship. Court, newspaper, and other records show that, between the 1850s and about 1900, an underclass with its own rules and customs existed on the streets of Halifax just below the citadel. This underclass manipulated -- and was not manipulated by -- the institutions devised to control or help it. Fingard demonstrates her point with a lucid statistical study of 92 petty criminals. Then, viewing the situation from another angle, she analyses the functions, both intentional and accidental, of the missions, hostels, schools, and other establishments set up to relieve the poor, often by reforming them. Fingard's most striking discovery is that neither racism nor sectarian hatred featured prominently in the underclass life of Halifax until social activists deliberately built these attitudes into their good works.