"Quantum Physics of the Solid State: an Introduction" Draft foreword: 26/09/03 If only this book had been available when I was starting out in science! It would have saved me countless hours of struggle in trying to apply the general ideas of the standard solid-state text-books to solve real problems. The fact is that most of the texts stop at the point where the real difficulties begin. The great merit of this book is that it describes in an honest and detailed way what one really has to do in order to understand the multifarious properties of solids in terms of the fundamental physical theory of quantum mechanics. University students of the physical sciences are taught about the fundamental the ories, and know that quantum mechanics, together with relativity, is our basis for understanding the physical world. But the practical difficulties of using quantum mechanics to do anything useful are usually not very well explained. The truth is that the application of quantum theory to achieve our present detailed understand ing of solids has required the development of a large array of mathematical tech niques. This is closely analogous to the challenge faced long ago by theoretical astronomers in trying to apply Newton's equations of motion to the heavens -they too had to develop a battery of theoretical and computational techniques to do cal culations that could be compared with observation.