An international group of scholars presents a very important development in the theory of relaxation processes. For the first time, the basic equations of motion have been put into a form suitable for computation of a variety of observable phenomena in several different disciplines. This book begins with a description of the foundations of the memory function techniques, of the adiabatic elimination procedure and of the mathematics of continued fractions. It also covers depth relaxation phenomena in several areas of physics, chemistry, biology, electronic engineering, spectroscopy, computer simulation and astronomy.