'The authors show complete technical mastery of their subject and of the mathematical methods required … contains a considerable amount which is new, both conceptually and in a mathematical tightening-up of earlier work and gives a full and modern account of its subject … a full, clear and authoritative account which certainly advances the current stage of the subject. The text is to be firmly recommended to time series analysts, actual and aspiring, and to the more mathematically valiant of the engineers.' P. Whittle, Journal of Time Series Analysis