The so-called man pages are the original UNIX help system format.
Man pages are static documents, as opposed to more modern hypertext systems.
They are often written in a very formal and stylized way that makes them somewhat inaccessible to the average user. However, for simple commands they are usually sufficient to learn the basics. The man page format tends to break down for large and complicated programs. Even for these programs, however, the man page is useful to see the available options for a program. A UNIX man page begins with a synopsis of how to invoke a command, followed by a more verbose description of the commands purpose.