I am currently working my way through classical Yang-Mills theory with the help of John Baez's book on gauge fields and some others. I have recently just began to notice the new, well new to myself, research on higher gauge theory. This looks very interesting but I feel that my background in category theory is too weak to actually understand everything that is going on. This seems to be a recurring theme as I try to advance my knowledge of mathematical physics. Last semester I took a course on topological quantum field theory and another on quantum groups and I feel that I did not get a lot out of it due to the amount of category theory that was used. So my question is this: does anyone know of a good reference for learning category theory? I have looked at Mac Lane's book but find a bit "spooky" with the amount of set theory he uses. Thanks for the help.