This volume contains the lectures presented at the summer school "New Insights into the Universe" held in Valencia, 23 - 27 September 1991, at the Universidad Internacional Menéndez Pelayo.

The seminar was organized with the aim of facilitating interaction of Ph.D. students interested in modern aspects.of cosmology with the community of experienced cosmologists. The contact was achieved successfully and we hope that the publication of this volume will extend it to a larger number of people interested in cosmological research.

The main topics overviewed are: the spatial distribution of galaxies and peculiar velocity fields, the lens effect and its cosmological observational consequences, and the microwave background radiation: spectrum and anisotropies.

Each of these subjects has been developed in various lectures. We asked the authors for a common structure in the presentation of the topics, giving firstly a general theoretical framework, and then an updated account of the observational status of the field. We thank them for the care they have had following our suggestion.

Bruce Patridge presented a nice basic lecture about the microwave back- ground radiation, covering both theoretical and observational aspects, but as much of it was presented at a previous meeting held in Rio Janeiro, his lecture is not included in this volume. It will be published elsewhere by Kluwer. The lectures on the anisotropies of the cosmic background radiation by Nicola Vittorio had to be omitted, since it was not possible for Prof. Vittorio to prepare a manuscript at present.

We take here the opportunity to thank the Universidad Internacional Menéndez Pelayo and the Universitat de València for financial support and administrative assistance. We also thank both lecturers and students for their interest in the lectures and discussions, and Prof. R. Kippenhahn, who refereed the volume for publication by Springer Verlag.

València
May 13, 1992

V. J. Martinez
M. Portilla
D. Sàez