The following people have helped during the 1.9 series:

Andy Wingo <wingo@pobox.com>
 - Several patches, especially in the "generic function creation
   speedup" area.

These people have contributed to 1.3 and before:

Clifford Beshers <beshers@ohanlon.mcl.cs.columbia.edu>
 - Input on interface design
Mikael Djurfeldt <mdj@nada.kth.se>
 - Fixed some ANSI compiliance problems
Klaus Schilling <klaus@pessoa.none>
 - Helped debug Makefile and initialization process
Dominique Sidou <sidou@eurecom.fr>
 - Helped with C++ support in guile
Donovan Kolbly <donovan@rscheme.org>
 - Has helped some with RScheme support
Mark Horning <rip6@rip6.net>
 - provided initial rpm spec file.
Robert Graham Merkel <rgmerk@mira.net>
 - much work on design and code.
Dave Peticolas <dave@krondo.com>
 - Various patches, bugfixes, RPM spec details, etc.
Derek Atkins <warlord@mit.edu>
 - Various patches, bugfixes, RPM spec details, etc.