  The ESO Slice Project (ESP) is a galaxy redshift survey we have recently
completed as an ESO Key-Project. The ESP covers 23.3 square degrees in a region
close to the South Galactic Pole. The survey is nearly complete (85%) to the
limiting magnitude b_J=19.4 and consists of 3342 galaxies with reliable
redshift determination. In this paper, the first in a series that will present
the results of the ESP survey, we describe the main characteristics of the
survey and briefly discuss the properties of the galaxy sample. From a
preliminary spectral analysis of a large sub-sample of 2550 galaxies we find
that the fraction of actively star-forming galaxies increases from a few
percent for the brightest galaxies up to about 40% for the galaxies fainter
than M= -16.5. The most outstanding feature in the ESP redshift distribution is
a very significant peak at z ~ 0.1. The detection of similar peaks, at the same
distance, in other surveys in the same region of the sky, suggests the presence
of a large bidimensional structure perpendicular to the line of sight. The
minimum size of this structure would be of the order of 100 x 50 Mpc,
comparable with the size of the Great Wall.
