In its 10th year, the International LISA Symposium of 2004 was the first to be organized by ESA. After the first Symposium at the Rutherford Appleton Laboratory in 1996, and subsequent Symposia at Caltech (1998), the Albert Einstein Institute in Golm (2000) and Penn State University (2002), ESA's European Space and Technology Centre (ESTEC) is proud to have hosted the 5th International LISA Symposium in 2004 in conjunction with the 38th ESLAB Symposium.

During these 10 years, we have seen the technology required for such ambitious space missions as LISA and LISA Pathfinder developing and maturing to a point where flightlevel hardware can be produced and tested. The technology demonstrator LISA Pathfinder has become a mission well established in the ESA programme and has entered its project implementation phase; the LISA mission is in the formulation phase.

At the same time, the preparations for LISA data analysis and first activities on data archives and LISA simulators have begun, indicating that LISA is regarded as more than just a mission far in the future.

The astrophysics of the sources of gravitational waves is emerging as a rapidly growing field that will become even more important in the coming years, when the focus of the activities on LISA and LISA Pathfinder will shift from making the missions possible to deriving scientific results from the data.

The 5th International LISA Symposium had presentations on all of the above topics, from the technology of LISA and LISA Pathfinder, LISA data analysis, and modelling and simulation, to the astrophysics of the sources. The programme included an overview of the activities at the ground-based detectors, with which LISA shares not only a common technological heritage but also the prospect of detecting gravitational waves in the next 10 years.

Such a conference would not be possible without the help of many people, not least the Scientific Organizing Committee, and the local organization, provided by ESA's conference bureau and Research and Scientific Support Department, that established the framework for an excellent and memorable conference. This having been set, it was up to the speakers and the participants to make the Symposium a success - a task that they performed spectacularly well.

The 6th International LISA Symposium in 2006 will be held in Annapolis, MD, USA, organized by NASA, an event to which I look forward with anticipation.