Introduction to Category Theory

Question

I would like a book or PDF file that teaches the basics of category theory using basic abstract algebra (groups, rings and modules) as an example.

For me, the ideal book is "Algebra: Chapter 0", written by Paolo Aluffi. I'd like something as similar as possible to this book. I don't use this book because unfortunately I don't have money at the moment to buy it. I also don't want to download an illegal copy of that book because it is piracy.

Could somebody please indicate me some free (or at least cheap) material similar to that book?

Answer 1

I have never really looked into it myself, but I once found "Category Theory in Context" by Emily Riehl, which can be downloaded from her university webpage. The title at least suggests that it might be worth a try for you.

Answer 2

A great and accessible book which introduces the basic ideas is Basic Category Theory by Tom Leinster, which is made freely available in PDF format on ArXiV.

He uses algebraic structures such as groups and modules, as well as topological spaces in most examples.