Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Unique and distinguished quaility

Well, I guess if you've come to this page, you have already heard of these famous books and why they're so wanted. So all I want to say is about the quality of the product. They're three books (The Lectures) plus the Tips On Physics. They come inside a box, which safely store them all, without loosenesses. All of the books are hardcovers, it feels like cloth, amazing. The pages are of higher density, which will make the books last long enough for two generations or more, for humidity or microorganisms won't affect the page so easily. They're very thin, but won't be a problem for a careful reader.My recommendation: you've lost enough time reading reviews. Just buy it.