After the preceding chapter “Toward the Need for Dynamical Systems Modeling in Psychopathology: Features of Mental Disorder that Any Explanatory Theory Must Consider and Key Definitions Thereof” of this volume provided an overview of critical issues for formally conceptualizing serious psychological problems such as mental disorder, or psychopathology, the current chapter now proceeds to sketch a theory intended to encourage process explanation, computational modeling, and mechanistic discovery. The proposal emphasizes that importance of a dynamic systems perspective including recognition of system level (emergent) properties. It proposes that the best solution to the complexity problem is to search for common pathways that cut across much of the nosology; that regulatory systems at distinct levels or units of analysis are the most promising candidate for such a common pathways framework; and that important discoveries are possible within each unit of analysis, including epigenetic regulation of gene expression, regulatory networks in the brain, and psychological mechanisms of self-regulation such as appraisal and construal, among others. The theory sketch is outlined, specific hypotheses are proposed that can be tested, and challenges are noted.