The cognitive behaviour therapy (CBT) emphasis on treatment relevance in assessment, and on evidence-based intervention, has led to an increasing focus on problem maintenance factors (vs. precipitants) in both its models of psychopathology and in its individual case formulations. This article describes the reasons for this growing focus, and presents a generic CBT model based on the functional analysis of "problem-maintaining circles" (PMCs) of causes. Some samples of the profuse literature implicating PMCs in many psychological disorders are presented, and the utility of PMC-based functional analysis, case formulation, or modelling of psychopathology is advanced, not only as a guide to selection of therapeutic interventions, but as an alternative to standard psychiatric diagnosis. A sampling of a taxonomy of such PMCs is presented. And finally, the clinical application of PMC-based functional analysis, case formulation, and treatment selection is illustrated in five case illustrations drawn from a recent clinical caseload. (Contains 1 table and 8 figures.)