[TeaBrain]

That particular passage in the Wikipedia article on the eponymous book being satire is worded extremely poorly. Satire is a common format for making social commentary. The occurrence in organizations of Lawrence Peter's findings, now known as the Peter Principle, is the social commentary being communicated by the book. It is a phenomenon which had previously been established as occurring prior to the book in Lawrence Peter's research and was the entire basis for the eponymous book being written by Raymond Hull.