Most users of the roff
language employ a macro package to format
their documents. Successful macro packages tend to ease the composition
process; their users need not have mastered the full formatting
language, nor even some of its major features like diversions, traps,
and environments. A familiarity with some basic concepts and mechanisms
common to macro packages (like “displays”) remains helpful; this
chapter aims to bring you to this level. If you prefer a meticulous and
comprehensive presentation, try gtroff
Reference instead.