There is a schism between science and practice in understanding and assessing personality. Approaches derived from the research laboratory often strike clinical practitioners as clinically naive and of dubious clinical relevance. Approaches derived from clinical observation and theory often strike empirical researchers as fanciful speculation. In this article, we describe an approach to personality designed to bridge the science-practice divide. The Shedler-Westen Assessment Procedure (SWAP; Shedler & Westen, 2004a, 2004b; Westen & Shedler, 1999a, 1999b) is an empirically rigorous diagnostic method that preserves the richness and complexity of clinical case description. In this article, we describe its use in diagnosis, case conceptualization, and treatment planning. We review evidence for reliability, validity, and clinical utility. Finally, in the article, we present a system for personality diagnosis, as an alternative to Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; American Psychiatric Association, 2000) Axis II, that is empirically grounded, clinically relevant, and practical for routine use in both clinical and research contexts.