Statistics of cosmological density fields -- Large-scale structures and motions: Linear theory and statistics -- Clusters of galaxies as probes for the large scale structure -- Galaxy formation with gravitation, hydrodynamics and active star formation -- Secondary anisotropies in the CMB -- The Relikt missions: Results and prospects to detect the microwave background anisotropy -- ROSAT observations of clusters of galaxies -- Statistics of gravitational lensing 1: Strong lenses -- Statistics of gravitational lensing 2: Weak lenses.

Indispensable for the building of cosmological models are precise observational data. To provide such data is the main purpose of this book. First, an analysis of recent cosmological observations using artificial satellites and large ground-based telescopes is given. Among these are the observation of the spatial distribution of galaxies and clusters, the detection of peculiar velocity fields in large regions, and the measurement of anisotropies in the microwave background radiation. Second, the authors present theoretical models which best fit the given observational data. The book addresses graduate students and astronomers and astrophysicists.