Psychological assessment is based on the psychology of individual differences and dates back to the beginnings of scientific psychology. Clinical psychology began as a profession that provided psychological assessment, and through the 1950s assessment was what most clinical psychologists did the majority of the time. The value and propriety of psychological assessment was subsequently challenged on various grounds, and other activities gradually supplanted diagnostic testing as a preferred career role among clinical psychologists. Despite predictions of its demise, assessment has continued to be the second most frequent professional activity of clinical psychologists, after psychotherapy. Instead of fading away, psychological assessment has thrived over the years, as evidenced by organizational recognition, substantial practice activity, and an extensive and expanding literature. Because of the singular significance of appreciating and measuring individual differences, because of the demonstrated utility of psychological assessment in facilitating decisions in a broad range of applications, and because of the professional satisfaction that derives from functioning as an expert diagnostic consultant, psychological assessment is here to stay. Psychological Assessment Is Here To Stay This article begins with some definition of psychological assessment and a bit of its history. Next, it reviews the flourishing of assessment psychology and how it weathered attacks on its utility and propriety. The discussion continues with evidence that assessment has remained a prominent part of clinical psychology and reasons to believe that it is here to stay. The conclusion calls attention to concerning trends in the field of psychological assessment. Defining Psychological Assessment Three characteristics define the nature of psychological assessment. First, psychological assessment consists of a variety of procedures for evaluating characteristics of people, including evaluations of intellectual ability, personality functioning, neuropsychological status, aptitudes and achievement, and interests and attitudes. Second, psychological assessment is rooted in the psychology of individual differences, that is, how people resemble each other and how they differ from each other. Third, although psychological assessment has sometimes been equated with psychological testing, the assessment process involves integrating information obtained from test protocols, interviews, behavioral observations, collateral reports, and historical documents.