Quality control has been with us for a long time. How long? It is safe to say that when manufacturing began and competition went together with manufacturing, consumers started comparing and chose the most attractive product. If manufacturer A discovered that manufacturer B’s profit was flying, the former tried to improve his / her offerings, probably by improving the quality of the output, and /or lowering the price. Improvement of quality did not necessarily stop with the product but also included the process used for making the product. The process was held in high regard, as obvious by the medieval associations of the middle ages. These associations mandated long periods of training for apprentices, and those who were aiming to become master craftsmen had to demonstrate evidence of their ability. Such procedures were, in general, aimed at the maintenance and improvement of the quality of the process. In modern times we have professional societies, governmental regulatory bodies aimed at assuring the quality of products sold to consumers. Quality Control has thus had a long history. On the other hand, statistical quality control is comparatively new. The science of statistics itself goes back only two to three centuries. And its greatest developments have taken place during the 20th century. The earlier applications were made in astronomy and physics and in the biological and social sciences. It was not until the 1920s that statistical theory began to be applied effectively to quality control as a result of the development of sampling theory. The first to apply the newly discovered statistical methods to the problem of quality control was Walter A. Shewhart of the Bell Telephone Laboratories. He issued a memorandum on May 16, 1924 that featured a sketch of a modern control chart. Shewhart kept improving and working on this scheme, and in 1931 he published a book on statistical quality control.