The assignment events, objects, state of beings, etc., to an experiential category is a fundamental activity carried out by human (and by other animals). So rudimentary are the processes involved in categorizing that it is indeed impossible to imagine conscious awareness to exist without the presence of categories. A considerable body of writing exists on categories dating from the times of Classical philosophy. Plato developed a categorical ontology and Aristotle produced one of the earliest examples of a complex understanding of basic ontologies. A number of other categorially structured ontologies have been proposed including those by Lowe, Westerhoff, Chisholm, etc.  The book is an edited collection of up to the moment essays that address critical aspects on the understanding of categories and categorial systems. The perspectives included in the book are drawn from philosophy, psychology, theology, divinity, comparative cognition and facet theory. The authors are all renowned experts in the area of their writing. Topics addressed include both contemporary advances in the understanding of perennial debates and latest thinking upon how categories are employed to structure our experiences of the world we live in. The book is distinct as being written by philosophers and psychologists. The book is a collection of writings from selected academics at the fore of debates and understandings of categories in contemporary thought. The text provides a single source for contemporary scholarship in categories. No single text that brings together expositions of categorial experiences for students and academics within the above listed disciplines.