books.google.co.uk - Category theory is a general mathematical theory of structures and of structures of structures. It occupied a central position in contemporary mathematics as well as computer science. This book describes the history of category theory whereby illuminating its symbiotic relationship to algebraic topology,...http://books.google.co.uk/books/about/Tool_and_Object.html?id=nVVsp3_Jw0sC&q=mappings&utm_source=gb-gplus-shareTool and Object
