In my amazon shopping cart I currently have: *Conceptual Mathematics: A First Introduction to Categorieshttp://www.amazon.com/gp/product/052171916X/ref=ord_cart_shr?ie=UTF8&m=ATVPDKIKX0DER *- F. William Lawvere *Categories for the Working Mathematician (Graduate Texts in Mathematics)http://www.amazon.com/gp/product/0387984038/ref=ord_cart_shr?ie=UTF8&m=ATVPDKIKX0DER *- Saunders Mac Lane *Categories and Computer Science (Cambridge Computer Science Texts)http://www.amazon.com/gp/product/0521422264/ref=ord_cart_shr?ie=UTF8&m=ATVPDKIKX0DER *- R. F. C. Walters Are all 3 of these worthwhile? Any of them? I'm just trying to get a grasp on enough Category Theory to be able think more deeply about programming in general, and maybe grasp more Haskell terminology beyond the seemingly superficial meanings I understand today. Thanks! Dave