Since the ?rst meeting in Lyon in 1986, the biannual European Turbulence Conferences have provided an informative survey of the international e?orts in understanding turbulence in its fundamental and applied aspects. Now integrated into the conference cycles coordinated by the European Mechanics Society the meetings provide a regular forum for the exchange of ideas and the discussion of the latest developments. The more recent conferences in Barcelona (2000), Southampton (2002), Trondheim (2004), and Porto (2007) have attracted several hundred participants from 30 and more countries. The 12th meeting in this series, ETC 12, which was held in Marburg September 7-10, 2009, continues this tradition. Researchers from 34 countries submitted 336abstractstotheconference. Thenumberofsubmissionsissomewhatlower than for the Porto or Barcelona meetings, but in line with the previous ones in Northern Europe. The contributions that were presented in Marburg were selected by the international advisory board for the European Turbulence Conferences. The committee was chaired by Professor Arne V. Johannson (Stockholm) and consisted of Professors Helge I. Andersson (Trondheim), Konrad Bajer (W- saw), Luca Biferale (Rome), Claude Cambon (Lyon), Hans-Hermann Fe- holz(Berlin),PeterDavidson(Cambridge,UK),YuriKachanov(Novosibirsk), Detlef Lohse (Twente), Jose L. Palma (Porto), Jean-Francois Pinton (Lyon) and the local organizer. Impressedbythehighqualityoftheabstracts the committee selected 250 for oral presentation, corresponding to a record number of almost 75% of the submissions. In addition, 70 papers were selected for presentation in a poster and seminar session. These numbers attest to the healthy state of the ?eld and the reputation the conferences have achieved.