As the first structures to collapse, galaxy clusters have to be seen as the earliest fingerprint of galaxy formation and evolution. A crucial epoch for galaxy evolution and formation are the first billion years of the universe (beyond redshift z=1) coming along with an enhanced starformation and black hole activity compared to the local universe and a huge growth of stellar mass both in cluster and field galaxies.

We will focus on the formation of these high-density environments and the evolution of their star-formation activity in the distant universe. The contributions will be based both on observational and theoretical studies spanning the whole range of the electromagnetic spectrum. Following key topics will define the framework of our symposium:

-formation of (proto)clusters in the early universe and their evolution over cosmic time;

-(proto)cluster search techniques;

-evolution of the star-formation activity and star-formation rate density (relation) in clusters at different epochs;

-molecular gas properties and star-formation efficiency of galaxy cluster members.