This document will serve as a guide for defining functional, performance and interface requirements for a system. This guide will recommend methods for specifying the requirements and capabilities for systems. System specifications developed using this guide will: 1) Facilitate a contracting agent to specify requirements for a system to potential designers/developers. 2) Provide templates for writing/auditing system specifications, and 3) Provide a general overview of a system which may be required by trainers, support personnel, or other users. Once completed, this guide will provide a foundation on which an IEEE tutorial on Developing System Specification can be built.