  We describe a large sample of 598 galaxy clusters and rich groups discovered
in the data of the Faint Sky Variability Survey. The clusters have been
identified using a fully automated, semi-parametric technique based on a
maximum likelihood approach applied to Voronoi tessellation, and enhanced by
colour discrimination. The sample covers a wide range of richness, has a
density of ~28 clusters per sqdeg, and spans a range of estimated redshifts of
0.05 < z < 0.9 with mean <z> = 0.345. Assuming the presence of a cluster red
sequence, the uncertainty of the estimated cluster redshifts is assessed to be
\~0.03. Containing over 100 clusters with z > 0.6, the catalogue contributes
substantially to the current total of optically-selected, intermediate-redshift
clusters, and complements the existing, usually X-ray selected, samples. The
FSVS fields are accessible for observation throughout the whole year, making
them particularly suited for large follow-up programmes. The construction of
this FSVS Cluster Catalogue completes a fundamental component of our continuing
programmes to investigate the environments of quasars and the chemical
evolution of galaxies. We publish here the list of all clusters with their
basic parameters, and discuss some illustrative examples in more detail. The
full FSVS Cluster Catalogue, together with images and lists of member galaxies
etc., will be issued as part of the ``NOAO data products'', and accessible at
http://www.noao.edu/dpp/. We describe the format of these data and access to
them.
