It has been a huge challenge to try to write the whole story of infrared astronomy, from the discovery of infrared radiation from the Sun by William Herschel (1738–1822) in 1800 through to the present day, to the discoveries being made by the space mission named after Herschel. I wanted to make this story accessible to the general reader with some interest in science but no scientific background. At the same time I wanted to make it a full and accurate account. Having lived and worked through the great period of infrared astronomy, from the 1960s to the present, I know many of the major figures whose work is described here, and I wanted to do them justice.

To reach the general reader, I have had to continually simplify the text, moving more complex and detailed material to the notes. Astronomy is a branch of physics, and physics is not an easy subject for someone who has perhaps not even studied it at school. I’ve provided a glossary of technical terms and tried to keep them to a minimum. The notes and very full bibliography allow the interested reader to explore the full details of a major area of science.

I have written about what I know, the science of infrared astronomy, and haven’t attempted to give the full story of the technological developments required to make this science possible. To give some idea of the huge army of people who work to provide the tools for science, an infrared space mission generally involves more than one thousand people in its design and construction. I was drawn into infrared astronomy in the early 1970s by my friend, and colleague at Queen Mary College London, Peter Clegg.