Documentation of commands for selecting fonts, as well as those for defining the data-structures used by the selection commands.

For further guidance, two papers may be helpful — “Essential NFSS” by Sebastian Rahtz, written shortly after the appearance of LaTeX2e, and “Font selection in LaTeX” by Walter Schmidt.

Fntguide is part of a set of documentation that also covers new LaTeX 2e commands, class and package writing, typesetting Cyrillic, LaTeX font encodings, configuration options and modification of latex.

The author is LaTeX Team.