Roughly a century has passed after the first ideas by Oliver Lodge, George Francis FitzGerald and Kristian Birkeland about particle clouds emanating from the Sun and interacting with the Earth environment. Only a few decades after the formulation of the concepts of a continuous solar corpuscular radiation by Ludwig Biermann and a solar wind by Eugene Parker, heliospheric physics has evolved into an important branch of astrophysical research. Numerous spacecraft missions have increased the knowledge about the heliosphere tremendously. Now, at the beginning of a new millennium it seems possible, by newly developed propulsion technologies to send a spacecraft beyond the boundaries of the heliosphere. Such an Interstellar Probe will start the in-situ exploration of interstellar space and, thus, can be considered as the first true astrophysical spacecraft. The year 2000 appeared to be a highly welcome occasion to review the achievements since the last COSPAR Colloquia 11 years ago, to summarize the present developments and to give new impulses for future activities in heliospheric research.