"Computer science" endures the disadvantage of a doubly inappropriate name. It is neither about computers, nor is it a science in the sense used of physics, chemistry, biology and the other empirical sciences. It is about programs, and about the technology of building programs. It cannot now be called "program engineering", however, because it has hitherto been preoccupied with discovering the principles discussed here: it is not the application of known science, the way mechanical, chemical, and electrical engineering are.