Cosmology has dramatically evolved during the last decade and there has been vast development of, e.g., theories of galaxy formation in connection with the early universe or gravitational lensing. These new developments motivated the editors to organize a school covering all of these ideas and observations in a pedagogical way. The topics covered in the 26 lectures of this summer school include: QSO absorption systems, identification of objects at high redshift, radiogalaxies, galaxy formation and evolution, galaxy number counts, clustering, theories of structure formation, large-scale structure and streaming motions, gravitational lensing, and spectrum and anisotropies of the cosmic microwave background radiation. Observational developments, data analysis, and theoretical aspects are equally treated.