The main objective of the contributions contained in this volume is to present the thermodynamic foundations of the response of elastic and dissipative materials. In particular, the governing equations of non linear thermoelasticity and thermoinelasticity as well as the basic properties of these equations as resulting from the primary assumptions of continuum thermodynamics are derived. The global formulation of thermodynamics of continua is discussed. A special attention is paid to the properties of the balance equations on a singular surface. The possible forms of the second law of thermodynamics are discussed within the frame­ work ofaxiomatic thermodynamics. Furthermore, the thermodynamiG requirements for differ­ ent kinds of materials are examined. The secondary purpose of the Course was to discuss some connections between rational and classical formulations of the principles of thermodynamics. The present volume contains the texts of three (of the four delivered) Course lectures. I hope it will constitute a useful source of information on the problems presented and discussed in Udine. Special thanks are due to the International Centre for Mechanical Sciences whose direction encouraged us to prepare and to deliver the lectures.