hp2xx was originally written in the early 1990s by Heinz W. Werntges
and is currently being maintained by Martin Kroeker 
(martin@ruby.chemie.uni-freiburg.de OR mk@daveg.com)
who gladly acknowledges contributions by 
(alas, this list is probably incomplete - please remind me if your 
name should be on it):

Emmanuel Bigler
Andrew Bird
Gerhard Buergmann
Eugene Doudine
Steve Edmonds
Lars Erikson
Francisco Filho
Bengt-Arne Fjellner
Joe Green
Serge Ivachenko
Michael Kennedy
Reinhard Kotucha
Michele Liberi
Bruce Lightner
Simon Munton
Ian McPhedran
Kazutaka Nishiyama
Yves Nodet
John Reeve
Michael Rooke
Georgy Salnikov
Michael Schmitz
Rolf Schreck
James D. Shaw
Yuri Strelenko
Georg Viehoever

and bug-hunting by:
Bernd Bartmann
Uwe Maleck
Thomas Mirlacher
Tyler Mitchell
Laurent Santona
Stephan Meystre
Christian Steigies
Piotr Szwed
Michael Kennedy
David Billinghurst
Wilfred van Rooyen