This book is full of necessary advanced grammar and multiple example sentences. I wish that the book was in English because if my Japanese was so advanced to be able to read this book easily...I would not need the book to begin with :)
But even if you have to either struggle through the sentences or just take the grammar pieces by themselves (every piece of grammar is written either in kana or kanji with furigana) and look them up on the Internet, do it! This book is the only source that I have ever seen that has a COMPREHENSIVE list of advanced grammar. This 104-page book has 173(!) grammar points and accomplishes more for only $39.99 than 1,000 pages of expensive textbooks can do because all of the busy work, cultural notes and padding have been removed.