This volume contains the lectures and participant contributions delivered at the Sixth Training Course in the Physics of Correlated Electron Systems and High-Tc Superconductors. Different from usual workshops, this course was designed to promote active participation of senior and young researchers and to introduce them to some specific problems. Lecture topics include: Introduction to Renormalization Group and Ward Identities in Critical Phenomena and in Fermi and Bose Liquids; Local Moment Physics in Heavy Electron Systems; and Transport of Strongly Correlated Electrons. Other contributions include: Theoretical de Haas-van Alphen Data and Plasma Frequencies of MgB2 and TaB2; Magnetic and Orbital Ordering in Doped Manganites; A Combined Exact Diagonalization - ab initio Study of the Metallicity and Electron Localization in Nanoscopic Systems; A New Spinwave Expansion for the Ordered Kondo Lattice; and The Novel Superconducting Clathrates.