The initial version was a shell program written by Evan Kirshenbaum. It was very slow and contained many bugs.
A new version was written in C by Miguel Santana to improve execution speed and portability. Many new
features and improvements have been added since this first version.
Many contributions (changes, fixes, ideas) were done by a2ps users in
order to improve it.
From the latest version from Miguel Santana (4.3), Emmanuel Briot
implemented bold faces for keywords in Ada, C and
C++.
From that version, Akim Demaille generalized the pretty-printing capabilities, implemented more languages support, and other features.
Masayuki Hatta maintained a2ps for several years. Later, David Seifert modernized and cleaned up the code considerably. Latterly, Reuben Thomas did more clean-up and bug-fixing, and released version 4.15, the first release for many years.