On behalf of the International Program Committee (IPC) and the Local Organizing Committee (LOC), we would like to welcome all participants of the IUCr-XXI Congress and General Assembly to Osaka. The year of 2008 is special for IUCr to celebrate its 60th anniversary. A celebration ceremony, which is open to general citizens, is scheduled prior to the Opening Ceremony on the first day (Aug. 23). The lecture by the Ewald Prize winner is also given at the Opening Ceremony. Scientific programs of the highest possible quality are prepared for the following 7 days (Aug. 24-30) with a great effort by IPC members and Chairs/Co-Chairs who have shared with us the burden and responsibility for selecting excellent topics and speakers.

　　　The City of Osaka has been a crossroads for people, goods, culture and information, even since the Middle Ages. All have passed through and met in Osaka historically, giving birth to something new and valuable. The modern City of Osaka has played an even greater role as a crossroads of international exchange while crystallography plays a role of crossroads of a wide variety of scientific fields as the most multidisciplinary sciences. Therefore, we have anticipated something new and exciting in IUCr-XXI.

　　　A participation by students and young crystallographers is particularly important for IUCr; therefore, we have made significant efforts in raising funds to support them as many as possible. Such a financial support has been made possible by IUCr and many generous contributors to whom we are deeply thankful. We have also greatly appreciated various organizations and companies, whose participation and sponsorship are crucially important for the success of IUCr-XXI.

　　　Now we trust that all participants will enjoy scientific and social activities and will find something new and exciting during the Congress in Osaka.