Since 1950, when the first million tons of plastic were produced worldwide and used in the market, the success story of this carbon-based class of materials has continued unabated to this day, based on its almost infinite variability (“made-to-measure material”) and high functionality. An understanding of the basic physical material and service properties in the most important areas of application and of the life cycles of the material in the various applications is necessary to give the often polemically conducted discussion about the advantages and disadvantages of this important class of materials an objective and thus target-oriented direction in the sense of the circular economy. The chapter is supplemented by aspects of economic efficiency, the nature of plastics and a brief description of the types of plastics produced today and available on the market.