The essay is concerned with library science as a science of the artificial. This is an area of research that has in recent decades gone through a profound change. The Aristotelian paradigm has made room for an interactice, technologically oriented applied science. This development has transformed the very concepts of book, library and information. Section 2 addresses the concept of book and the history of bookmaking. Section 3 is dedicated to the historical background of libraries. Section 4 concerns the state of the art of modern library science. Section 5 clarifies, how librarians are trained in their profession and which requirements they are expected to satisfy.