I would like to thank you, Marc, for your great contribution to the organisation of the complicated and fast growing virus world - the speed of which you would have never expected as you admitted on your birthday.

Viruses need a new definition at times where sequences indicate viruses but where hosts, tropism or diseases are not known and cannot even be determined. What is a virus - more unclear than ever. Your groundwork will be the fundament for the huge challenge for future of the virus world.

Marc, you together with Brian Mahy, issued the most useful and pretty Desk Encyclopaedia on Viruses, four classical books, which young researchers or medical doctors can afford. It is my standard present for colleagues and students und timeless in spite of all the new changes in virology.

Marc, you like to lecture - which you spontaneously did during an EMBO Global Exchange Lecture Course I organized in Stellenbosch/South Africa on HIV/AIDS in 2011. You were provoking the audience with your broad knowledge, ideas, and thoughts in - very - demanding presentations!

I personally owe you the publication of a “personal view” on “What contemporary viruses tell us about evolution” in the Archives of Virology (Vol. 158, 2013) which was “your” journal for so many years. Now at times where astrophysicists become astrobiologists searching for life on exoplanets - this article attracts unexpectedly acute attention. You accepted it, allowing provocative views.

Thank you, Marc, and best wishes for the years to come. With admiration and gratitude

Karin Moelling