A discussion of Integrated Logistics Support (ILS) concepts and techniques. The purpose of ILS is to insure that the system effectiveness goals are compatible with the capabilities of the support base. The estimate of logistics requirements calls for models which relate logistics with operations and valid historical data on logistic costs and consequences. Analytical models are apt to be used during the early stages for parametric analyses, gross tradeoff analyses, and, possibly, marginal analyses between different design concepts. As the system matures simulation models may be needed. ILS models can establish design goals, which, when fixed, can serve as contract specifications for the system developer; they can also monitor the developer's progress and insure that design decisions are desirable in the operating and policy environment of the system user. The choice of models also depends on their treatment of the parameters and their relevance to the real world. 33 pp.