This book examines the foundations of personal belief by conducting a review of classical and contemporary thought about beliefs, by experimenting with new and innovative ways to conceptualize beliefs and by presenting new evidence about beliefs from empirical studies. Beliefs, although often vaguely defined in discourse, can be conceptualized in many different ways: as associative memories; as coactivations between multiple neural assemblies; as functional cognitive instruments; as self- propagating entities that parasitize minds; as the firings of a certainty module in the brain; as placeholders for self-identity; or as means by which to make sense out of the world. This book explores each of these very different facets of belief in an endeavor to explicate the origins and dynamics of believing. Concepts that are considered include personal epistemology, delusional thinking, unconscious processes, the neurobiology of belief, the ontology of belief, and the evolutionary pressures on belief accuracy. The viewpoints garnered, although they come from disparate fields, interface in provocative ways and taken together, paint a rich portrait of the mechanics of belief.