The large-scale structure of the Universe and systems Clusters, and Groups of galaxies are topics like Superclusters, They fully justify the meeting on "Clusters of great interest. and Groups of Galaxies". The topics covered included the spatial distribution and the clustering of galaxies; the properties of Superclusters, Clusters and Groups of galaxies; radio and X-ray observations; the problem of unseen matter; theories concerning hierarchical clustering, pancakes, cluster and galaxy formation and evolution. The meeting was held at the International Center for Theoretical Physics in Trieste...

The 1980's have been times of great excitement in Astrophysics and Cosmology. Professors Dennis Sciama and Fabio Mardirossian and all the other Members of the Organizing Committees are to be congratulated for having given us a taste of this excitement in Trieste, by inviting the leaders of the subject to the meeting they have organized. The excitement has corne from the new observations of the three-dimensional structure of the universe through a large number of new measurements of redshifts. These have revealed that clusters of galaxies are distributed on the surface of big empty bubbles of...