This is a collection of lectures on topics in cosmology and elementary particles with emphasis on astrophysics. Delivered by prominent scientists, the lectures give up-to-date and comprehensive treatment of the areas covered.

The last decade has seen fruitful interactions between elementary particle physics and cosmology. Developments in the theories of broken symmetry, gauge interactions and supersymmetry have opened up new possibilities for the history of the early universe, while astronomical data on cosmic expansion, baryon-entropy ratio, galactic structure and elemental abundances have set constraints on particle theories. The First Jerusalem Winter School aimed at presenting a systematic account of these topics, from the physical and astronomical fundamentals to the latest progress.

In the last few years there has been a revival of interest in the old idea that spacetime may have more than four dimensions, all but four having been curled up into a small circumference. In this view the various particles and interactions we see at ordinary energies arise from a simple, perhaps purely geometrical, theory in higher dimensions. This idea has profound implications for elementary particle physics and cosmology, and raises challenging problems of mathematics. These matters were the topic of the Second Jerusalem Winter School of Theoretical Physics.