The purpose of this manual is to provide a reasonably detailed
overview of the source code and programming philosophy of \PSIfour,
such that programmers interested in contributing to the code will have
an easier task.  Section \ref{svn} gives a succint explanation of the
steps required to obtain the source code from the main repository at
Virginia Tech.  (Installation instructions are given separately in the
installation manual or in \$PSI4/INSTALL.) \ref{Style} offers advice on
appropriate programming style for \PSIfour\ code, and section \ref{Makefiles}
describes the structure of the package's \file{Makefile}s.  Section
The appendices provide important reference material,
including the currently accepted \PSIfour\ citation and format
information for some of the most important text files used by
\PSIfour\ modules.

There are many examples included in this document to provide sample input files
and source files; these can be found in ASCII form in the \PSIfour\ source
itself.  Each included file has a path, which is relative to
\$PSI4/doc/progman, as its title and this is where the unformatted file can be
found.  The examples described herein can even be compiled from the directories
in which the source files are found.

Mention the GPL and development policies...

