The book describes in detail a number of techniques for modelling and presenting the data you collect. It also describes User Environment Design, a techique I have found useful for approaching the problem of translating data into interface designs. It is particularly useful if you do not have strong skills in visual design. A 'must have' book is Jakob Nielsen's 'Usability Engineering' . This is an excellent introduction to the philosophy and practice of usability.
Cooper has some harsh words to say on the subject of usability.
He also has a very interesting and rather unflattering persepctive on the psychology of programmers. Although not a 'usability' book, 'The New Drawing on the Right Side of the Brain' by Betty Edwards is a great introduction to drawing.