I'm using a version of this book which has a different cover to the one advertised, so hopefully this means that there is a new version of this book, which has fixed all the errors mentioned in other reviews. But, while this book is good for practicing higher level questions, many of the solutions are at best dubious, or at worst blatantly wrong/contradictory - which make it very confusing to use. I've used other similar publications and not been aware of such poor accuracy. Not to be recommended.