This is about "mass market paperback" edition. Probably very interesting book. Unfortunately, I am not able to read it. Production quality is extremely poor. Format is small, about a postcard size, font is 8pt. Pring is blurred, dark gray, on light qray, extremely poor quality paper. Font intensity and blurness is different on almost each page. Even with magifying glass reasing reading is hard.Returning to Amazon and will invest more monies to purchase "not mass market" edition