This document discusses object-oriented analysis and design (OOAD) requirements. It covers what requirements are, which include statements describing what a proposed system must do or constraints on its development. Requirements must contribute to solving the customer's problem and be agreed upon by stakeholders. Requirements can be functional, describing what the system should do, or non-functional, describing quality, performance, design, platform, and process constraints. Examples of functional requirements include system inputs/outputs and computations. Non-functional requirements constrain the system's quality, performance, design, environment, and development process.