The writer Mark Twain once joked, after a journey abroad, that the purpose of eternity was to give Americans the chance to learn German. After grappling with the language in earnest for more or less than a decade, Mr. Clemens' words are starting to lose their humorous quality and take on more than a grain of truth. I have an MA in Germanistik (German Studies), and even the head of my department who has her PhD and has lived in Germany for decades, always had her work checked by a native speaker, and some Germans I know claim she continued to make minor mistakes here and there (though her overall faculty with the language was stellar), especially when speaking extemporaneously. In short, German is very, very hard, for those whose mind (Language Acquisition Device for you Chomskyans) is already hardwired-set to read and interpret English.
This workbook, which I've used probably now for more than a year, is not a magic bullet, but it has corrected many of the defects that I routinely made in things like word order, the double-infinitive, and various exceptions to rules that are hard to follow and even harder to remember.
Is my German perfect after reading this book? No. Will I ever be able to speak as fluently as, say, Thomas Mann? Heck-to-the-naw, as the kids used to say back in my day. But I am speaking better German, so the book has met, if not exceeded, expectations. Recommended for those anywhere on their journey with the German language, from first year students to those who've been speaking for years but maybe want a refresher (the appendices alone make the book essential for those who don't want to constantly be cross-referencing with online dictionaries and databases every time they forget the simple past form of some subjunctive II verb or something).