"I propose to study the dynamical and nonthermal processes in the intracluster medium (ICM) by combining a phenomenological analysis of observational data, a theoretical study, and dedicated numerical simulations.The proposed research is designed to address the central open questions in the theory of clusters, resolve the present tension between observations and simulations, distinguish between different theoretical models, and prepare for future observations.One main goal of the research is to disentangle the distributions of cosmic-rays, magnetic fields, and turbulence in the ICM, and identify their origins, evolution, and implications.A second goal is to facilitate a self-consistent model for the cool cores observed in the centers of most clusters, by identifying the mechanism that stabilizes the core against cooling, the feedback processes that render it robust, and the role played by active galactic nuclei and global flows.The research is motivated in part by the apparent lag of ICM theory behind the recent observational progress and the present numerical capabilities. In particular, it would utilize the recent observations of cold fronts, spiral patterns, and radio minihalos, that appear to exist in most cores."