Book is well composed, definitions of the words and phrases are very easy to understand. And reading of this book gave me many fascinating hours and a lot of good mood. Some words (and phrases) have direct equivalent in my language (I'm Russian), so it amused me a lot. At the same time I think (it's my own opinion only) that patwa is mangled english (although is accepted as independent language by some people). Look - in russian we have a lot of unique phrases, cadences in different regions, unique verbs, but nobody call that features as independent russian. The same situation in chinese language - people from different provinces even don't understand each other. So, I think that patwa isn't separate language (guys and girls, who are proud of patwa - don't understand me wrong way, if you give me weighty arguments I'm able to change my viewpoint).
And one likkle( :) ) drawback of the book - it don't have information about markers in patwa (markers of tenses), and pronunciation rules of another words, not included in dictionary. It would make sense to include that information. But I have found that information by myself in the internet, so, all is fine.