Hierarchical Clustering

In this contribution I present current results on how galaxies, groups, clusters and superclusters cluster at low (z≤1) redshifts. I also discuss the measured and expected clustering evolution. In a program to study the clustering properties of small galaxy structures we have identified close pairs, triplets, quadruplets, quintuplets , etc. of galaxies in the Sloan Digital Sky Survey commissioning imaging data. An analysis of the 2-point angular correlation function on an area of more than 250 square deg 2 show that these objects appear to be appreciably more strongly clustered than single galaxies.