Competence, in the context of criminal justice proceedings, refers to a defendant's capacity to meaningfully participate and make decisions during the criminal justice process. Competence is relevant at any stage of the process, from a defendant's first words to arresting officers, through that defendant's decision about pleas, until-in the gravest of cases-the moment of execution. Because questions about competence can be raised at any point in criminal justice proceedings, this chapter describes criminal competencies, and many scholars use broad terms such as adjudicative competence (see Bonnie, 1992) or competence to proceed, to cover the span from arrest to verdict to sentencing. Nevertheless, this chapter focuses primarily on the defendant's capacities that comprise his or her competence to stand trial because this is, by far, the most commonly adjudicated competence (Melton, Petrila, Poythress, & Slobogin, 2007), and far more scholarly research literature addresses this particular competence. Authorities estimate that at least 60,000 defendants-approximately 5% of all felony defendants-are evaluated for trial competence each year in the United States, making trial competence assessments the most common form of criminal forensic mental health assessment (Bonnie & Grisso, 2000;Poythress, Bonnie, Monahan, Otto, & Hoge, 2002). Most practicing clinical forensic psychologists evaluate trial competence on a routine basis. Indeed, evaluating, adjudicating, and restoring competence consumes most of the financial resources that jurisdictions devote to forensic mental health services (Golding, 1992).1 Although the Godinez decision has been understood as holding that the same competence standard applies to any actions that a defendant may take (i.e., waiving counsel and pleading guilty), a more recent case has modified this understanding. In Indiana v. Edwards (2008), the U.S. Supreme Court considered the unusual case of a mentally ill defendant who not only waived counsel but represented himself at trial (rather than simply pleading guilty, as in Godinez). The Court decided that the state could indeed limit this defendant's right to represent himself, even though he met the Dusky standard for trial competence, because self-representation in trial requires greater capacities. Thus, the recent Edwards decision suggests that the standard for competence may indeed vary in at least some circumstances.