Chapter 2 is by far and above, the most difficult part of the book. This is because groups are written in additive and multiplicative notation, and the concept of coset is confusing at first. After Chapter 2 it gets easier as you go along. Indeed, after the first four chapters, the linear algebra follows easily. The present situation with college textbooks is a national disgrace.
Textbooks are too big and too expensive.
I was determined to speak right to the student and to have a short book, but keeping it under control was not easy. I worked at it off and on for fourteen years. It came out a little unusual, not by accident or oversight, but because I designed it that way. It is almost entirely the product of my will. Unfortunately mathematics is a difficult and heavy subject.