The present work is dedicated to Dr. Gerhard Herzberg, who did so much for the knowledge of H2 and many other molecules. It was initially undertaken under the auspices of the International Tables of Selected Constants (Paris) and CNRS (Centre National de la Recherche Scientifique), which provided useful advice and encouragement. Over the years, many people helped the authors to complete this long term project.

First of all, credit must be given to Dr. Henri Damany for designing the low pressure gas discharge lamp, twenty five years ago, when he was at the Laboratoire des Hautes Pressions (Meudon-Bellevue). Thanks are due to Dr. Christian Jungen (Orsay, France) and to Dr. Michel Larzillière (University Laval, Québec, Canada) who contributed at the early stage of the work. We appreciated the help of Maurice Benharrous in taking pictures and photoelectric recordings. Microdensitometer traces were carefully done by Monique Clemino. Professor Jean-Louis Subtil (University of Saint-Etienne) wrote the file handling software required by the great number of data. Rosario Battaglia assisted in entering and checking the data. We also acknowledge the help of Dr. Stephane Mottin (University of Saint-Etienne) in the task of editing the tables in the proper format. The greatest contribution came certainly from Dr. Hervé Abgrall (Meudon Observatory), who performed the semi-ab initio calculations of emission probabilities and line positions that were so necessary to identify many features of the spectrum. Finally we would like to thank all of those who encouraged us to pursue this project in spite of the disregard of some people for what they term "grandpa's spectroscopy."