Tom Leinster’s book Basic Category Theory arrived today on the new book shelves at the CUP bookshop. I just love the opening two sentences, which seem about as good a minimal sketch of what category theory is up to as you could hope for:
Category theory takes a bird’s eye view of mathematics. From high in the sky, details become invisible, but we can spot patterns that were impossible to detect from ground level.
That’s a brilliantly promising start: and thirty pages in, the book is still proving a really good, if moderately taxing, read.