Walter Shewhart is considered the grandfather of Total Quality Management. He brought together statistics, engineering, and economics to formulate a scientific basis for quality control. Some of his main contributions include developing statistical process control (SPC) methods using control charts, pioneering statistical quality control (SQC) techniques, and creating an early version of the PDSA/PDCA improvement cycle that is still used today. Shewhart's work in the 1920s at Bell Labs laid the foundation for modern quality management practices.