These subdirectories contain source code to all of the
programs printed in the book, as well as a number of
libraries which are necessary or useful to build
certain programs.

The subdirectories contain:

c                               Source code for all C programs
cgic104                         Source code for the cgic C library
gd1.2                           Source code for the gd C library
perl                            Source code for all Perl programs
perllibs                        Several Perl libraries, including GD.pm