This book is intended for one-quarter or one semester-courses in homological algebra. The aim is to cover Ext and Tor early and without distraction. It includes several further topics, which can be pursued independently of each other. Many of these, such as Lazard's theorem, long exact sequences in Abelian categories with no cheating, or the relation between Krull dimension and global dimension, are hard to find elsewhere. The intended audience is second or third year graduate students in algebra, algebraic topology, or any other field that uses homological algebra.

From the reviews: "The book is well written. We find here many examples. Each chapter is followed by exercises, and at the end of the book there are outline solutions to some of them. [...] I especially appreciated the lively style of the book; [...] one is quickly able to find necessary details." EMS Newsletter