Human-defined systems have characteristics of interest, such as size, monetary value, or output rate. Their change in a desired direction is considered an improvement. Self-improvement is when the change comes from internal action of the system. It has occurred throughout history in many ways, such the as evolution of life, or the development of civilization. But these changes have often been random rather than purposeful. This book discusses self-improving systems generally, but it is mainly about a new type of production system - a Seed Factory. This is a starter set of equipment specifically designed for growth and self-improvement. It does this by a recursive process, which has the potential for exponential growth. There are many uses for seed factories, and more generally for systems that are designed for self-improvement. We present several examples in the later sections of this book, and incorporate the concept in a companion book on Space Systems.