What's the best "Learn Polish" book?

Yes, for sure. It's the best book for learning Polish I have ever seen.
People should also get 301 Polish Verbs by Janecki.
Doskonała kombinacja. :)

Up near the top of this thread, Edyta recommends some books from the publisher Universitas. Since she wrote that, their collection of titles for learners of Polish has expanded massively. Seriously, check out their website - it's a revelation....

I already had a couple of books and have just bought this one, and I have to agree with SzwedwPolsce. There were a number of things that I was struggling to get my head around with the others, but I have only flicked through this and looked at the first couple of chapters and it is already starting to make more sense!