This chapter discusses the important topic of process monitoring using so-called control charts. These are devices for the routine and organized plotting of process performance measures, with the goal of identifying process changes. When these are detected, those running the process can either intervene and set things aright (if the change is detrimental) or try to make permanent the source of an unexpected process improvement. The discussion begins with some control charting philosophy in Sect. 3.1. Then the standard Shewhart control charts for both measurements/“variables data” and counts/“attributes data” are presented in consecutive Sects. 3.2 and 3.3. Section 3.4 discusses qualitative interpretation and practical implications of patterns sometimes seen on Shewhart charts and some sets of rules often applied to check for such patterns. Then there is a presentation of the so-called average run length concept that can be used to quantify what a particular process-monitoring scheme can be expected to provide in Sect. 3.5. Finally, in Sect. 3.6 the chapter closes with a discussion clarifying the relationship between “statistical process control” and “engineering control” and presenting some basic concepts of so-called proportional-integral-derivative (PID) engineering control schemes.