I make it a habit to read as many of the urban sketching books as I can, as they're all unique in some way, even if just in the art examples that they show. This book is like many, in that it's an introduction to the art form, and not highly technical (I think that's a good thing). The really cool and unique thing about this book is that it doesn't just focus on pen/ink/watercolor - there are some nice tips and examples for painting in oils, especially.

Overall, perhaps the best thing to say is that after I read my library copy, I ordered a copy of the book for my own shelves at home.