A description of some of the background, and results of research concerned with effective use of fire department manpower and equipment and, particularly, with deployment and allocation of firefighting units. The work described is part of the interdisciplinary research program conducted jointly, since early 1968, by the Fire Department of the City of New York (FDNY) and the New York City-RAND Institute. The report discusses some major problems urban fire departments face and outlines strategies pursued in developing research to solve them. Detailed descriptions focus on deployment issues and the many analytical and computer models created to examine them and generate new policies to meet FDNY needs. The report then discusses some results that these models have yielded, describes briefly what putting these results into practice has involved, and notes what some practical experience has been.