This program owes much to other similar programs in operation at many radio-astronomy observatories. The basic functionality and data structure were strongly influenced by Colin Spratling's MANIP, which was written for the InSb receiver at UKIRT. The idea of using a stack and RPN arithmetic was borrowed from Paul Rayner's program SPCRED, which was in use at CSIRO's Division of Radiophysics in 1976/77. Buddy Martin at Cambridge, Gary Fuller at Berkeley, and more recently John Richer at MRAO, have all acted as guinea-pigs for the program development. The command language has evolved over the years, but I thank John Richer particularly for his clear views on what was and what wasn't acceptable. Richard Prestage at JACH and John Lightfoot at ROE both did a great deal of work to interface SPECX to GKS graphics, and to make it available through Starlink -- I hope that the change to a graphics-package independent interface results in less work for them with SPECX_V6.2 and subsequent versions. More recently Remo Tilanus at JACH has provided much useful feedback which has enabled me to fix problems more speedily than in the past. Horst Meyerdierks at ROE is currently working on the UNIX version. I am grateful to Keith Shortridge for permission to use his routines to write FITS data files.
I especially thank Thomas Walker, one-time JCMT Telescope Operator, who compiled the V5.3 SPECX Cookbook, which greatly enlightened the users and showed me how many improvements there were still to make (many of the improvements in later versions exist only as a result of the deficiencies described in the Cookbook).