What makes ModelBuilder attractive for a crime analysis unit is its potential to string complex tasks together and automate them to run regularly. Crime analysts need a mapping program that enables them to regularly update crime occurrences and their locations. ModelBuilder assists crime analysts by expediting their daily tasks of creating crime maps that show an updated picture of what crimes are occurring where and in what numbers and patterns. ModelBuilder, which comes standard with ArcMap version 9.x, is an advancement of ArcView 3.x's Geoprocessing Wizard Extension. Whereas the Geoprocessing Wizard was limited to tasks such as spatially joining, merging, and clipping data, ModelBuilder has all of ArcMap's functional capabilities. In addition to providing a general description of ModelBuilder's capabilities, this article provides a step-by-step description of how the user gets started with the software, how to find and use its tools, and how to geocode data with a composite 1.0 geocoding service. The example provided in ModelBuilder's latter function uses two layers, a street file and a geofile, in ordering the automatic location selection process inherent in a composite address locator. The article concludes with a description of how ModelBuilder can be used to create "kernel densities" for hot-spot mapping, i.e., the location of areas where crime in general and/or specific types of crimes are occurring more frequently compared to other areas of an agency's jurisdiction. In its detailed description of the use of ModelBuilder, the article assumes that the reader is sitting at a computer with the ModelBuilder software displayed on the screen. 3 figures and 7 notes