In this chapter, terms relating to liming are explained, and an introduction to the importance of liming and the need for liming of agricultural crops is given. The extent of suboptimally limed areas in Germany is described and the causes for the suboptimal lime supply are mentioned. After introducing the principle of lime requirement determination, the influences of incorrect soil information and their causes are outlined, and resulting losses are pointed out. Thus, the need for site-specific, sensor-based liming is explained, and ultimately the motivation for this book is given. Precise liming requires a workflow of various steps in a networked system. Reference is made to their description in the following chapters. In this chapter, the reader is introduced to the terminology in the framework of liming. The importance of liming and the need for liming of agricultural crops is highlighted. Statistical evidence for insufficient pH management in Germany is given and causes for the suboptimal lime supply are discussed. After introducing the principle of lime requirement determination, the impact of erroneous soil information and their causes are outlined, as well as resulting yield losses. A solution to this problem is a more precise liming which regards site-specific requirements using sensor-based information. The necessity to provide sound knowledge on precision liming motivates this book. Precise liming comprises a workflow of various steps in an interconnected system. This workflow is briefly introduce and references are given to the detailed description in the successive chapters.