Job analysis is the process of discovering the nature of a job. It typically results in an understanding of the work content, such as tasks and duties, understanding what people need to accomplish the job (the knowledge, skills, abilities, and other characteristics), and some formal product such as a job description or a test blueprint. Because it forms the foundation of test and criterion development, job analysis is important for personnel selection. The chapter is divided into four main sections. The first section defines terms and addresses issues that commonly arise in job analysis. The second section describes common work-oriented methods of job analysis. The third section presents a taxonomy of knowledge, skills, abilities, and other characteristics along with worker-oriented methods of job analysis. The fourth section describes test validation strategies including conventional test validation, synthetic validation, and judgment-based methods (content validation and setting minimum qualifications), emphasizing the role of job analysis in each. The last section is a chapter summary.