Category Theory is all about composing things and being able to reason about them mathematically. In programs, we compose lots of things (functions, types, obje

Category Theory is all about composing things and being able to reason about them mathematically. In programs, we compose lots of things (functions, types, objects, systems...), and being able to abstract that away is valuable. Bartosz Milewski has been putting together a nice series ("Category Theory for Programmers") for a little while now, that seems to be pretty well-received and may give you the answer you're looking for: http://bartoszmilewski.com/2014/10/28/category-theory-for-programmers-the-preface/ http://bartoszmilewski.com/2014/10/28/category-theory-for-pr...