the core of this multi-band project. The infrared coverage with WISE, the dedicated spectroscopic survey with AAT/AAOmega and the Shapley-VISTA survey, together with other proprietary data, provide the fundamental data-set to achieve the scientific goals of ShaSS. In this article we will give an overview of the project and present the first results. In Sect. \[objec\] the motivations and main scientific objectives of the project are discussed. The target is described in Sect. \[SSC\]. The characteristics and strategy of the survey are described in Sect. \[survey\]. Details of the data reduction and analysis of the data quality are given in Sects. \[DR\] and \[DA\], respectively. The first results concerning the characterization of the environment are presented in Sect. \[results\], where we derive the galaxy density across the whole ShaSS region and the underlying dark matter distribution for the central 1deg$^2$ field which allows to estimate the mass of the galaxy cluster A3558. In Sect. \[sum\] we present the summary and conclusions.

Throughout the paper we adopt a cosmology with $\Omega_M$=0.3, $\Omega_\Lambda$= 0.7, and H$_0$=70kms$^{-1}$Mpc$^{-1}$. According to this cosmology 1arcsec corresponds to 0.941kpc at $z$=0.048 and the distance modulus is 36.66. The magnitudes are given in the AB photometric system.

Survey 