Like most Irish people, I went through years of state schooling in Irish and came out barely able to string a sentence together. The fact that the system insisted we study the language from books like this didn't help. These days I use interactive software which I find much more successful. The book is all about genitive case, declensions and all the kind of stuff that put you to sleep at school. However, it is quite comprehensive and if used sparingly as a reference when you hit a particularly knotty linguistic problem it can be useful. Just don't try to study it cover to cover.