Toward a deeper understanding of minds, whether natural or artificial, and of how they are studied and built across AI, AGI, and cognitive science.Minds are functional entities that enable intelligent behavior. In On Minds, Paul Rosenbloom offers reflections and perspectives on the study of minds arising from a multi-decade career focused largely on cognitive architectures—hypotheses concerning the fixed structures and processes that yield a mind, whether natural or artificial. Cognitive architectures must be integrative in accommodating the full range of capabilities required of a mind. They must also be general, in applying across many, if not all, problems and domains. This breadth of investigation, across a sequence of three such architectures—XAPS, Soar, and Sigma—and over many years, has inspired a set of reflections on both cognitive architectures and three core disciplines within which such work occurs—artificial intelligence (AI), artificial general intelligence (AGI), and cognitive science.The book’s reflections are of three types. The first explores four concepts critical to understanding minds—architectures, symbols, intelligence, and theories—to provide new perspectives and insights on them. The second rethinks the structure of the space of technologies that underlies work on minds, yielding multidimensional maps that clarify their similarities and differences plus detailed insights into the tradeoffs that exist across both individual technologies and integrated systems—whether symbolic, neural, or hybrid—built from them. The third traces the author’s decades of work on architectures—including cognitive architectures, the Common Model of Cognition, and the nature and structure of computing as a great scientific domain—interwoven with personal reflections and anecdotes.