The last few years saw the development of a plethora of experiments and surveys probing the cosmological parameters. The Cosmic Microwave Background (CMB), the Supernovae (SN) searches and galaxy cluster data, namely via X-rays and Sunyaev-Zel'dovich effect, are among the most prolific giving detailed information about the geometry, age and structure formation of the Universe.
The program of the WS-HCP workshop was aimed at highlighting the scientific achievements and to discuss the new environment of "precision cosmology" within these three probes. The objective was to analyse different observational strategies, common problems namely foregrounds, and to assess the impact of observational uncertainties in the determination of key cosmological parameters which describe the primordial universe and the large scale structure formation mechanism.