“What is he like?” As social beings, we are continuously interested in the behavior and personality of those we meet. We are curious if someone is quiet, honest, proud, anxious, funny, indifferent, perceptive, or introspective. Those characteristics influence our experience of others and affect the quality of our relationships with them. When these characteristics persist to varying degrees over time and across circumstances, we tend to think of them as personality. Certainly, we informally evaluate others’ personalities all the time, but the clinical assessment of personality using psychometrically robust tools is an important component of the professional practice of psychology.