Conceptual Mathematics is a good introduction to category theory (which is all about objects and morphisms) and especially well suited for self-study: http://www.amazon.com/Conceptual-Mathematics-First-Introduct...
Conceptual Mathematics is a good introduction to category theory (which is all about objects and morphisms) and especially well suited for self-study: http://www.amazon.com/Conceptual-Mathematics-First-Introduct...