ABSTRACT
In order to establish a foundation for relaxation theory, we will in this chapter provide a background by introducing the concepts of spin-lattice and spin-spin relaxation. We begin by looking at a simple example, which captures the basic principles of the nuclear spin relaxation without being directly applicable to any real physical situation. We use this simple example to introduce the important basic concepts within the theory of random processes and then to calculate transition probabilities driven by random processes. We look briefly at the prediction of the simple model and introduce the important finite temperature corrections to the theory.
