The author advises in the Preface: "This book was originally conceived to be a simple and straightforward verse-by-verse commentary on Galatians. However, in the course of preparing to do this teaching, it became clear to me that I could not just jump into composing a commentary on Galatians without first taking the necessary time to delve into a detailed treatment of the issues that Paul was facing in his time, hence, setting the stage for some essential background that is foundational to this commentary; this is what the first half of this book is about. Then, what follows in the second half is what I originally set out to do, which is to write a verse-by-verse teaching that you could reference as needed. "Now, before we get started, I want to speak concisely about two matters that will prove themselves to be fundamental to our right understanding of Galatians. The first is the subject of tradition, and the second is Rabbinic oral law and authority."
Basically I read only the first part of Avi Mordichai's book on Galatians, which provides a cultural and historical context for Paul's letter. I did not read the second part, which provides a verse-by-verse commentary. More than any book I know of, this book clarifies the issues Paul addresses in Galatians -- a confusion of written vs. oral law. Teachers were coming "from Jerusalem" turning Paul's converts from Torah faith to rabbinic authority -- from Moses to "the sages." In the first half of the book, the reader will come to understand that rabbinic authority is a form of "replacement theology," (my analogy) and the rationalizations for it. There is a brief muddled section on "the two house theory," that tries to synthesize too much information in a few pages of opinion. I disagree with a lot in that section, but otherwise definitely recommend the book. It has become rare and expensive. You can probably get it through your public library inter-library loan program.