The chapter introduces the fundamental concepts of systems analysis and design, emphasizing the importance of well-defined requirements for effective information systems. It outlines the system development life cycle (SDLC), which includes initiation, analysis, design, implementation, and maintenance phases. The SDLC is supported by various modeling techniques such as data flow diagrams (DFDs) and unified modeling language (UML) diagrams. The chapter also discusses the role of the systems analyst, the importance of stakeholder involvement, and the need for thorough testing and documentation during the development process. Additionally, it covers the advantages and disadvantages of different approaches, including structured analysis, object-oriented analysis, and agile methods. The chapter provides practical guidance on creating functional decomposition diagrams, identifying business processes, and drawing physical and logical DFDs, with a focus on maintaining data flow consistency across different levels of detail.The chapter introduces the fundamental concepts of systems analysis and design, emphasizing the importance of well-defined requirements for effective information systems. It outlines the system development life cycle (SDLC), which includes initiation, analysis, design, implementation, and maintenance phases. The SDLC is supported by various modeling techniques such as data flow diagrams (DFDs) and unified modeling language (UML) diagrams. The chapter also discusses the role of the systems analyst, the importance of stakeholder involvement, and the need for thorough testing and documentation during the development process. Additionally, it covers the advantages and disadvantages of different approaches, including structured analysis, object-oriented analysis, and agile methods. The chapter provides practical guidance on creating functional decomposition diagrams, identifying business processes, and drawing physical and logical DFDs, with a focus on maintaining data flow consistency across different levels of detail.