It contained a lot of words and example sentences I've never seen before. I would recommend using this after mastering all the grammar for N4. Else it wouldn't be a very productive read.
Also, the red plastic word hider thingy was pretty ingenious. I wish this technique could be used for more books.
Well structured, with a lot of examples, this book gives a comprehensive set of basic japanese vocabulary, mostly designed to the foreigner studying the language with a decent knowledge of the language. Very useful to review vocabulary and master everyday words.