This exposition of the theory of materials has its origins in the lectures I gave at the universities of Darmstadt and Kassel from 1978 onwards. Research projects carried out during the same period have been the source of extensive refinements to the subject-matter. The reason for adding yet another book to the existing wealth of volumes dealing with continuum mechanics was my desire to describe the phenomenological theory of material properties from my own point of view. As a result, it is without doubt a subjectively inspired and incomplete work. This particularly applies to the selection of quotations from the literature. The text has been influenced and enhanced by the numerous discussions I had the privilege of holding with students and experts alike. I should like to thank them all sincerely for their contributions and encouragement. 1 My special thanks go to my academic teachers Rudolf Trostel and Hubertus 1. Weinitschke,2 whose stimulating lectures convinced me at the time that continuum mechanics is a field of science worth pursuing. I greatly appreciate the long and amicable collaboration with Babis Tsakmakis and Manfred Korzen, during which a number of indispensable fun damental aspects emerged. Valuable inspiration regarding the development of the thermomechanical theory of materials was given by Roman Bonn, Markus Horz, Marc Kamlah and Alexander Lion. It was Lion''s skill that provided the link between the theoretical modelling and experimental investigation of material behaviour.
