In no particular order:

* John Pedersen, from John Wiley & Sons, Inc.
  for his detailed and constant feedback about high-quality rendering,
  combining characters and usage of TeX fonts. He's also been the first
  one compiling the tool under Solaris.

* Claudio Sacerdoti Coen,
  for his bug-reports and useful feedback for the GTK+ interface and
  the implementation of the <maction> element (toggle mode). He's also
  contributed into the development of various bindings for the OCaml
  language.

* Pouria Masoudi
  porting to GTK2 and Bonobo Control for GtkMathView

* Nathan Hurst
  feedback for cursor API

* Shuying Wang
  read-from-buffer methods in widget and gmetadom frontend

* Jean Brefort
  patches for configure.ac and auto/Makefile.am

* Hubert Figuere (hub), Francis James Franklin (fjf)
  MacOSX/fink port

* Robert Staudinger
  autopackage support

* Marc Maurer (uwog)
  Win32/mingw port

* Alessandro Appeddu
  MathML to SVG converter

* Nicola Rossi
  PostScript backend and accents