The Integrated Logistics Support (ILS) concept reduces weapon system logistics support costs by continually evaluating such costs entailed by a particular design, and then modifying the design. This report describes existing modeling techniques that can be used during weapon system conception, development, production, and deployment to investigate the logistics impacts of design decisions. The report is based on a sample of 46 models, which includes about half of all such models currently available, categorized according to their applications — spares, test equipment, personnel, maintenance posture, operations, life cycle costs, and project management. Current model technology is adequate for the support cost estimating required for implementing ILS in all phases of system acquisition. Designers should thus concentrate on adapting existing models to particular uses and fashioning sets of models into compatible families applicable to a wide range of problems.