Neutrinos play an intriguing role in modern physics linking central questions of particle physics, cosmology and astrophysics. The contributions in this book reflect the present status of neutrino physics with emphasis on non-accelerator or beyond-accelerator experiments. Since a nonvanishing neutrino mass would yield an important boundary condition for GUT, SUSY or Superstring models and since neutrinos are the best candidates for dark matter in the universe, the many efforts to look for a neutrino mass, ranging from neutrino oscillation experiments using reactors, accelerators or the sun as neutrino sources, to tritium decay experiments and the search for neutrinoless double beta decay, are described in some detail. One of the sections is devoted to neutrinos from collapsing stars, including the supernova SN 1987 A. Possibilities for detecting cosmological neutrinos are discussed and an outlook to future experiments is given.