This document provides an introduction to object-oriented analysis and design (OOAD) and the Unified Modeling Language (UML). It discusses the basic concepts of OOAD and how UML uses diagrams to model software systems. UML diagrams can be used in all phases of the software development life cycle, including requirements analysis, design, implementation, and testing. The document also gives an overview of the different parts of UML, such as views, diagrams, relationships, and model elements.