After trying a more expensive Polish course and finding it inadequete I was hesitant to try something so cheap, but I gave it a try and can't believe how great it is.
The course is well structured in easy to understand sections, guiding the learner through with thorough explanations of everything you have to learn to have a reasonable competency in polish. What makes this book a good buy for me is it assumes the reader has a decent level of intelligence and is not afraid to explain the grammar used in every section. In my opinion, you can never learn a language properly without understanding the grammatical aspects....phrases just aren't enough!
Along with the course content are a few excercises which test you on everything you have learnt beforehand. Although not extensive they are certainly effective.
The major bonus of this course for most readers will be the anglicised pronunciation guide. Every polish word in the book is followed by an english spelling of the pronunciation. While it is not perfect it is ideal for those who have no access to real polish speakers and gives you a close enough approximation to the language that a Pole will be able to understand you.
If you get this book, I advise buying a polish dictionary and possibly the book entitled '301 Polish Verbs' to give you some extra depth to your studies.
All in all, a great buy even at 4 times the price!