  We investigate the distribution of superclusters and voids using a new
catalogue of superclusters of rich clusters of galaxies which extends up to a
redshift of z=0.12. The new catalogue contains 220 superclusters of rich
clusters, of which 90 superclusters have been determined for the first time.
Two thirds of those superclusters with eight or more member clusters are
concentrated to a Dominant Supercluster Plane almost perpendicular to the plane
of the Local Supercluster. Several independent methods indicate consistently
the presence of a quite regular supercluster-void network with scale of approx.
120 Mpc. We determine the selection function of the sample of clusters and
suggest that the mean true space density of Abell clusters is 2.6 x 10^-5 h^3
Mpc^-3, or twice the conventionally used value.
