ALGEBRA Michael Artin

This book began about 20 years ago in the form of supplementary notes for my algebra classes. I wanted to discuss some concrete topics such as symmetry, linear groups, and quadratic number fields in more detail than the text provided, and to shift the emphasis in group theory from permutation groups to matrix groups. Lattices, another recurring theme, appeared spontaneously. My hope was that the concrete material would interest the students and that it would make the abstractions more understandable, in short, that they could get ferther by learning both at the same time. This worked pretty well. It took me quite a while to decide what I wanted to put in, but I gradually handed out more notes and eventually began teaching from them without another text. This method produced a book which is, I think, somewhat different from existing ones. However, the problems I encountered while fitting the parts together caused me many headaches, so I can't recommend starting this way. The main novel feature of the book is its increased emphasis on special topics. They tended to expand each time the sections were rewritten, because I noticed over the years that, with concrete mathematics in contrast to abstract concepts, students often prefer more to less. As a result, the ones mentioned above have become major parts of the book. There are also several unusual short subjects, such as the Todd- Coxeter algorithm and the simplicity of PSL2.