If only every language had a book like this you could read before undertaking a course in said language.
This is a slim volume, but packed full of useful information, including a brief history of the development of the Gaelic language, pronunciation, why letters are pronounced a certain way, and why it appears this language using more letters than others. Accents are explained as are long and short vowels, the changes for past/present/future tense, prepositions, counting (the old fashioned way) and differences in dialect and a likely explanation as to why they might occur. There is also explanations for words imported from other languages and their spelling and pronunciation.
All of which information gives you a head start when trying to read what's being spoken by your tutor, or sounded from your CD/computer. It all makes much more sense now and I don't feel so lost wondering where the sound originates.
Although this book is only 80 pages long, its a great reference and I will keep it close by whilst I learn Gaelic until I have its contents memorized and can fumble my way through written text, confidently sounding out the words using McLennan's explanations as a guide.