The first international DDECS Workshop was held in the Czech Republic in 1997. The Czech universities surely deserve a high appreciation for starting the Workshop and for defining its place in the professional life of Central Europe. Their traditional links with Polish institutions - especially in Silesia - suggest that the DDECS, before it develops into an event of truly international importance which we hope will happen in the near future, should be organized by Central European countries. Therefore, the DDECS 1998 was held in Poland, the third DDECS 2000 Workshop was held in Slovakia, the fourth DDECS 2001 was held in Hungary.