In our days astronomical research shows two trends – among others: On the one hand traditional astronomical plate archives are in danger of falling into oblivion while science is losing their information content. On the other hand there is an ever-growing need for long-term monitoring of large quantities of objects – the very information contained in the archives. On this background the workshop „Treasure Hunting in Astronomical Plate Archives“ was convened in order to discuss the scientific potential of the world‘s photometric and astrometric plate archives, ways of making them fully available to scientific research, as well as technical problems connected with this.