Tjhis presentation has been very useful for me: Category Theory for software engineers,. http://www.cs.toronto.edu/~sme/presentations/cat101.pdf It is an excelent introduction using basic notations (graphs). It includes "Applying category theory to specifications" and "Tools based on category theory" An excerpt: "Reading maths books (especially category theory books!) is like reading a program without any of the supporting documentation. There’s lots of definitions, lemmas, proofs, and so on, but no indication of what it’s all for, or why it’s written the way it is. This also applies to many software engineering papers that explore formal foundations" Additionally I would say that reading category theory books is like readling a program with no monoonomorphic instances, no semantic structure, no imperative main function telling what is all the stuff for, and no purpose.