Dear colleagues, Diffractive Optics 2005, 3-7 September 2005, Warsaw Uniwersity, Warsaw, Poland) is the continuation of a series of European meetings on the subject, which started with two workshops in Prague in 1992 and 1995. These workshops evolved into the EOS topical meetings held in Savolinna in 1997, in Jena in 1999, in Budapest in 2001 and in Oxford in 2003. The aim of these conferences is to bring together scientists and engineers interested in the use of microstructured optical components and wave optics in optical designs and applications. Exchange ideas with your peers! Share your research with other international leaders in the field of diffractive optics. Diffractive optics has wide ranging applications in biotech, telecoms, security and many other disciplines. This time we will meet at the Warsaw University, which was founded in 1816 and is one of the largest institutions of higher education in Central Europe. The investigations on diffractive optics have also a long tradition here. One of professors of the Faculty of Physics of the Warsaw University was the world-class Polish scientist Prof. Adalbert (Wojciech) Rubinowicz (1889–1974), one of the founders of quantum theory of radiation and theory of diffraction (“Rubinowicz-Kirchhoff diffraction integral”). Please join us for the next meeting on Diffractive Optics, visit our city and experience more than 1,000 years of Polish history and culture along with traditional Polish hospitality. You will be most welcome in Poland. Sincerely yours, Zbigniew Jaroszewicz Chairman of the DO2005 meeting