The investigation of the physical properties of matter has progressed so much during the last hundred years that today physics is divided into a large group of special branches, which are often very distant from each other. These branches arise because of the vast extent of the science itself, and are distinguished by the particular area studied, the method of investigation and so on. An independent and important branch that has developed recently is the physics of thin films. This deals with systems which have only one common property, namely, that one of their dimensions is very small,...