Naet companion is an A4 brochure which is recommended for purchase before any treatment is pursued...you should therefore also purchase the book. I thought it expensive, around 10. and disappointed that I could not really use the book. I suppose I mis-read the notes, but I had already thrown one away that I had bought on e-bay. A medical type brochure. I wish I hadn't wasted my money, you need to commit yourself to a specialist person first; then buy.