Ebook: Introduction to Algebra

Cameron's 2nd Edition is the first book I have seen in the market which is remarkably better than other similar "Intro" to Abstract Algebra for teaching undergrads who have never been exposed to New Math:

1) He places Rings (chap 2) before Groups (chap 3)- this is a very bold idea and I think very logical. Rings (like Z) are very familiar to normal high school students, so easier to understand than the more abstract Group theory.
Starting from Ring to learn factor ring, ideals, Laws of Isomorphism and other concepts, then revisit them later in Group will help to reinforce understanding.

2) He uses simple layman languages to explain complex concepts. For example: Homomorphism vs Isomorphism is akin to seeing things by short-sighted person without glasses (look similar) vs with glasses (exact image 1:1).