Since 1979, the U.S. Army Research Laboratory has been developing and distributing the BRL-CAD constructive solid geometry (CSG) modeling package for a wide range of military and industrial applications. The package includes a large collection of tools and utilities including an interactive geometry editor, ray tracing and generic frame buffer libraries, a network-distributed image processing and signal-processing capability, and an embedded scripting language. As part of this effort, a multivolume tutorial series is being developed to assist users in the many features of the BRL-CAD package. The Overview and Installation guide, which is the first volume in the series, addresses the background, purpose, and strengths of the package; the libraries and utilities included within it; platform-specific installation instructions; and information about bugs and updates. Other volumes focus on advanced features, individual utilities, and programming.