Ruud Janssen studied Physics and Mathematics. He became active with mail art in 1980 and did several international mail art projects. From 1994 till 2001 he has conducted interviews with Fluxus and mail artists in different communication forms; the results have been published in booklets and on the internet since 1996. In later years he focused more on acrylic painting and individual correspondences. He always maintains his site with the latest details of his work.

Janssen publishes articles, magazines and booklets with his TAM-Publications and participates in international mail art projects, collaborations and exhibitions. He founded IUOMA (International Union of Mail-Artists) in 1988 and is also the curator of the TAM-Rubberstamp Archive, the result of a Mail Art collection that has been accumulated by him from 1983 to 2004. The archive contains prints, original rubberstamps, magazines and literature. In 1994 he started with his Mail-interviews which have been published as booklets and online. The interviews have a new concept where the question is sent in a specific communicationform and the interviewed person chooses his own way to get the answer back. This way the factor time is involved in each specific interview. Samples of interviewed persons are: Ray Johnson, Dick Higgins, Ken Friedmann, Anna Banana, Mark Bloch, Patricia Tavenner, Michael Leigh and Guy Bleus.

In 2003 Ruud Janssen founded together with Litsa Spathi the Fluxus Heidelberg Center for which they are building up a collection of Fluxus material and where they also publish their own works.