Claus Madsen was born in Copenhagen in 1951. With an MSc in Science, he has spent most of his professional life with science-related activities, first and foremost in the service of the European astronomy organisation ESO. From an initial science assignment in astrophotography, he moved to public science communication and subsequently to science policy and science diplomacy. He has written extensively about astronomy, science communication, science policy, science history, and contemporary affairs in general and has given talks and lectures across the world.
Claus Madsen is also a photographer. He received his first formal training in 1971-74 at a Danish newspaper and at the Danish School of Photography and worked as a commercial photographer before turning his attention to science in 1980. In recent years, he has resumed his photographic activities and has published a number of photographic books.