"Scottish Gaelic in Twelve Weeks" has been written both as a self-tuition course for beginners and also for use within the classroom. You may want to learn Gaelic because of a general interest in Celtic or Scottish history and culture, or because it was the everyday language of your ancestors. The cynical observer may wonder if the exercise is worthwhile, when only one and a half per cent of Scotland's population speak the language. However, Gaelic is far from dead; in some parts of the Highlands and Western Isles it is the everyday language, and it represents an important part of the United Kingdom's cultural mix. There are Gaelic-learning classes in almost every area of Scotland. Each lesson in the book contains some essential points of grammar explained and illustrated, exercises, a list of new vocabulary (with a guide to pronunciation, in International Phonetics notation), and an item of conversation.
Roibeard Ó Maolalaigh is Professor of Gaelic and Vice Principal and Head of the College of Arts / Colaiste nan Ealain at the University of Glasgow, Scotland. He was born in 1966 in Dublin, Ireland.
It progresses rather quickly, I think. The knock against it is that self-teaching will probably be very slow for most. If you're really interested in picking up the language, you should probably go for the Edition with the audio CD included.
Great way to learn language words, but short on use of one word over another in sentences. Must be strongly self-motivated to stick with book to completion.