This is a great book for what it is - and what it is is a bare-bones Irish grammar, a supplement to a detailed primary source for learning Irish. Don't buy this book intending to use it as a primary source for learning Irish; it lists the basic rules of the language in an outline format, but it won't explain how those rules are employed. As a quick-and-dirty grammar it's been very useful. I am using Micheal O'Siadhail's book, "Learning Irish," which takes a very piecemeal approach to the language. So about once a week, for maybe 45 minutes, I go through relevant sections of McGonagle's grammar to get a more structured take on what I've been studying. I find that learning a foreign language is easier if you have two or three ways of approaching the same material at the same time. This grammar book is one of my three ways, and it's easily the most cost-effective one.