The present issue contains a series of papers presented at the 9th International ESTRO–Wolfsberg Meeting on Molecular Radiation Biology/Oncology. This series of meetings developed under the dynamic leadership of Professor Hans Peter Rodemann and his vigorous Scientific Committee, has set another highlight demonstrating that the field of radiobiology and its relation to development of radiotherapy has grown substantially over the years. Last year, Radiotherapy & Oncology for the first time published the highlight papers from the meeting, and the present issue contains the selected papers from the 2005 meeting [1–15] .T he realization of the growing importance of the research presented during the Wolfsberg meetings and the need to bring this research into a potential clinical application made it natural for ESTRO and the Wolfsberg organizers to officially formalize the collaboration and thus starting this year the ESTRO–Wolfsberg Meeting will become the flagship of clinically-related radiobiology in Europe. What really has made the Wolfsberg International Meeting a prime event has been the ability to recruit internationally highly qualified scientists where some and some not are working in close relationship with the clinical scenario. This has consequently resulted in a cross fertilization of ideas and concepts and has without doubt brought a more high-level basic scientific content into the platform of clinical radiobiology. Hopefully, it not only in turn benefits the cancer treatment of patients, but it has also made it clear for basic scientists that ionizing radiation is a very important tool for studying mechanisms of biological processes. The understanding of fundamental cell biology may often need an outside trauma to become obvious, and the two short review papers published in the current issue give a clear indication of that [16,17].