Gedcom is a very loose set of tags which can be used to label data about a person.

For example, INDI is used to specify an individual numerically in the database, NAME the person's name. The context/meaning is generally obvious: SEX, OCCU, MARR, SPOUSE, etc.

Levels are indicated by numerals. For example, the line

   1 BIRT
could be followed by the lines
      2 DATE Jan 3, 1988
      2 PLACE Worcester, MA, USA
to indicate the subsidiary nature of that date and place. Order is not particulary critical. SPOUSE could come before or after FATHER.

[The source code for book-latex.ll (which we shall be using later) contains a list of useages it prefers.]