Clusters of galaxies provide direct paths to the large scale structure (LSS) and global properties of the universe. Because clusters can be described in a physically meaningful way, their detailed astrophysical understanding is crucial for using cluster properties as precise cosmological probes, complementray to (and independent of) the very beneficial and intensely explored cosmic microwave background radiation.

Great progress has been made towards a more complete understanding of cluster formation and evolution, and physical characterization of their hot, dilute intracluster gas and dark matter (DM) components. This is made possible through detailed observations in the radio, microwave, IR, and X-ray, in addition to improved traditional optical measurements. Major new projects ensure that exciting progress will be made in the very near future towards a greatly improved understanding of the LSS and the parameters of the accelerating universe model, including its dark energy content.

Theoretical modeling, sophisticated fully N-body and hydrodynamical simulations, and analysis techniques have improved a great deal. The degree of theoretical detail is quite impressive, as is obvious from the fact that physical phenomena involving realistic cooling and heating mechanisms, non-adiabaticity, magnetic fields and non-thermal particles (observed by radio and X-ray emission), hydrodynamic turbulence, and energy feedback from supernovae and active galactic nuclei nuclei (thus linking clusters to the rich phenomena that occur in these powerful sources), need now to be more fully incorporated in the description of clusters. While many of the myriad of pertinent processes are well understood, taking a full account of their consequences is still a challenge.

Cluster research has evolved so much that extensive, varied expertise is now required to carry out the complex task of extracting astrophysical and cosmological information by contrasting detailed theoretical results with diverse datasets. The emergence of this research field as a dynamic, major area of astrophysics and cosmology - together with the tremendous observational and theoretical developments expected in the near future - provide strongl motivation for the School. It will be very timely to review pedagogically, within a unifying perspective, the major advances in the astrophysics of clusters, in order to provide junior researchers the necessary background and familiarity with methods and tools of galactic astronomy, high energy astrophysics, and cosmology.


The School will provide comprehensive pedagogical reviews of all major theoretical and observational aspects of physical processes and environments of clusters, the statistics of galaxy and cluster surveys, and joint analyses of large cluster X-ray, S-Z, and lensing datasets. We envision a School that constitutes a high level scientific forum and an excellent timely opportunity for junior scientists to gain the basic expertise needed to participate in multi-disciplinary collaborative projects on clusters. This will enhance cooperation in this highly competitive field.