I'd been learning to speak Thai for about four months using the Thai PDA 4xCD course from Linguaphone and a couple of online resources. My progress had begun to slow and I was in danger of losing interest when I bought this little book. Instantly, key questions and mis-understandings that had frustrated me were answered and corrected. It was like getting a simple, straight forward second opinion on something that had seemed just too complicated.
Included are words and phrases in ten topics for common situations, some very interesting cultural notes, grammer, plus a worthwhile English-Thai word list.
The best of it is being provided with the essential Thai you need in order to get speaking fast. It's when you start speaking the language that you really see the fun and progress.
So in a nutshell, I recommend 'Instant Thai' as a very useful supplement to more serious study. In particular, I believe it's essential to hear Thai spoken by native speakers as the phonetic Roman is spelt differently in every source I've seen and cannot interpreted without it.