If you are not serious about learning Irish you would waste your money on this course. There are lots of much cheaper phrase-books on the market. They won't teach you much, but you will learn some everyday phrases.
However, if you are serious about learning the language this course is a disaster.
- It is poorly organised. The grammar is presented in a very random way and you will have to jump from chapter to chapter to learn points of grammar since one piece of grammar can be split up between many chapters.
- It does not take you that far. It says "explore the language in depth" but that is something written on the cover of every new Teach Yourself book. It is true for some of the courses but definitely not for this one. You will have learned a basic vocabulary and some grammar by the end of this book, but you will be far from competent in Irish. Other courses take you much further.
- The language used in the course. Irish is divided into three dialects as well as a standard dialect. Amazingly, this course is not based on any of these. Rather, it takes some aspects from one dialect, some from another dialect and some from the standard language. True enough, Irish speakers will understand you but you will sound very strange - not unlike a foreigner speaking English mixing Oxford English, Texas English and Cockney.
- The pronunciation on the CDs. I've never heard a more stilted pronunciation in my life (and I've heard lots and lots of Irish). If you use this pronunciation you will be understood (altough those to whom you speak will be confused) but you yourself will not understand what you hear. Spoken Irish isn't anything near the pronunciation given here.
My recommendation is that you look up the excellent course "Learning Irish" here at Amazon. I've written a review of that course too, so I won't repeat myself except from saying that it is superior in every possible way.
(This review is based on the newest version of Teach Yourself Irish, 2004. The earlier edition is identical except from the cover and some web-sites.)