From the reviews: "e;Volumes III and IV complete L. Hormander's treatise on linear partial differential equations. They constitute the most complete and up-to-date account of this subject, by the author who has dominated it and made the most significant contributions in the last decades.....It is a superb book, which must be present in every mathematical library, and an indispensable tool for all - young and old - interested in the theory of partial differential operators."e; L. Boutet de Monvel in Bulletin of the American Mathematical Society, 1987"e;This treatise is outstanding in every respect and must be counted among the great books in mathematics. It is certainly no easy reading (...) but a careful study is extremely rewarding for its wealth of ideas and techniques and the beauty of presentation."e; J. Bruning in Zentralblatt MATH, 1987Honours awarded to Lars Hormander: Fields Medal 1962, Speaker at International Congress 1970, Wolf Prize 1988, AMS Steele Prize2006