en] This book contains the proceedings of the International Conference on the ''Highlights in Condensed Matter Theory'', held at the International Centre for Theoretical Physics (ICTP) in Trieste, Italy between August 1-3, 1989. The conference was organized to celebrate the seventieth birthday of Professor Kundan S. Singwi. It included mainly talks on many-body correlations in Fermi systems, dynamical correlations in classical liquids, and density functional theory. The conference also included two special colloquia, by Professors R. Moessbauer (''The Puzzling Neutrino'') and R. Peierls (''The Cold Big Bang'')