Download Algebra: Abstract and Concrete.
This book is being offered free of charge to anyone interested in learning abstract algebra.
The book provides a thorough introduction to "modern'' or "abstract'' algebra at a level suitable for upper-level undergraduates and beginning graduate students. The book addresses the conventional topics: groups, rings, fields, and linear algebra, with symmetry as a unifying theme.
The most important goal of the book is to engage students in the active practice of mathematics. Readers are asked to participate and investigate, starting on the first page.