Huggett moves on to introducing the technical ideas and apparatus, beginning with a classical example.  Simple string in an n-dim relativistic spacetime.  Introduces the notion of a string worldsheet and its internal coordinates.  The action (Nambu-Goto action) giving the law for this string will be one that minimizes the relativistic area.  A special metric h is introduced on the 2-d worldsheet of the string, which is not connected to the full spacetime metric g, and should not have physical import in the end.