This thesis addresses two very different but equally important topics in the very broad fields of astrophysics and cosmology: (I) the generation of cosmological magnetic fields and (II) gravitational fragmentation of the Cosmic Web. All mathematical developments are completed by illuminating physical interpretations, and the thesis, which is guided by existing observations, is purely theoretical. In part I, the author further develops a magnetogenesis model proposed in the literature, providing an unprecedented level of physical understanding. He demonstrates that the physics of photoionisation is very likely to have premagnetised, at a relevant level, the entire Universe at the early epoch of the formation of the first luminous sources. In part II, the author adapts the tools of plasma spectral theory to the context of gravitational instability of the baryonic gas within the stratified structures of the Cosmic Web. He skillfully derives the wave equation governing the growth of perturbations and explores various equilibrium configurations, in planar and cylindrical geometries characteristic of cosmic walls and filaments, for isothermal and polytropic conditions, with or without an external gravitational background. Clearly structured and written in pedagogical style, this outstanding thesis puts the results into perspective and highlights the merits and limitations of the various approaches explored.

The 1980's have been times of great excitement in Astrophysics and Cosmology. Professors Dennis Sciama and Fabio Mardirossian and all the other Members of the Organizing Committees are to be congratulated for having given us a taste of this excitement in Trieste, by inviting the leaders of the subject to the meeting they have organized. The excitement has corne from the new observations of the three-dimensional structure of the universe through a large number of new measurements of redshifts. These have revealed that clusters of galaxies are distributed on the surface of big empty bubbles of diameters of the order of 20-50 Mpc. Additionally, there is some evidence for invisible dark matter (whose composition is not known) as well as evidence for the gravitational lens effect. To cap this has corne the supernova of 1987, an event which last occurred 383 years ago. For the first time in history, the neutrino flux from the supernova was measured, giving limits to neutrino masses and numbers of neutrino types. (The dark matter problem is related to Particle Physics - beyond this standard model). It is good to be alive when all this happens and to try to comprehend this. Once again, our appreciation to the organisers and to those who presented their beautiful results.

The modern Persian word for cosmology is "Keyhan-shenakht", which is also the title of a Persian book written more than 800 years ago. The same term can also be found in Old Persian. In spite of this old tradition, modern cosmology is a new~omer within the scientific disciplines in Iran. The cosmology community' is small and not yet well established. Given the spectacular recent advances in observational and theoretical cosmology, the large amount of new observational data which will become available in the near future, and the rapid expansion of the international cosmology community, it was realized that Iran should play a more active role in the exciting human endeavour which cosmology constitutes. This was the main motivation to establish a School on Cosmology in Iran. The plan is to hold a cosmology school every three years somewhere in Iran. The focus of this First School on Cosmology was chosen to be structure formation, a rapidly evolving cornerstone of modern cosmology. The topics of the school were selected in order to give both a broad overview of the current status of cosmological structure formation, and an in-depth dis cussion of the key issues theory of cosmological perturbations and analysis of cosmic microwave anisotropies. The lectures by Blanchard and Sarkar give an overview of homogeneous cosmological models and standard big bang cosmology. In his contribution, Padmanabhan presents a comprehen sive discussion of the growth of cosmological perturbations.

This volume documents the theoretical and observational results and arguments in favour of (or against) the most preferred models of structure formation. New observational results of the large scale distribution of matter are confronted with recent theories on the origin and evolution of structure in the universe.

Proceedings of the 130th Symposium of the International Astronomical Union, dedicated to the memory of Marc A. Aaronson (1950-1987), held in Balatonfured, Hungary, June 15-20, 1987

A thorough and up-to-date graduate textbook on the most promising theory of the universe - inflationary cosmology.

This book contains a series of lectures given at the NATO Advanced Study Institute (ASI) "Structure Formation in the Universe", held at the Isaac Newton Institute in Cambridge in August, 1999. The ASI was held at a critical juncture in the development of physical cosmology, when a flood of new data concerning the large scale structure of the Universe was just be coming available. There was an air of excitement and anticipation: would the standard theories fit the data, or would new ideas and models be re quired? Cosmology has long been a field of common interest between East and West, with many seminal contributions made by scientists working in the former Soviet Union and Eastern bloc. A major aim of the ASI was to bring together scientists from across the world to discuss exciting recent developments and strengthen links. However, a few months before the meeting it appeared that it might have to be cancelled. The war in the former Yugoslavia escalated and NATO began a protracted bombing cam paign against targets in Kosovo and Serbia. Many scientists felt uneasy about participating in a NATO-funded meeting in this situation. After a great deal of discussion, it was agreed that the developing East West conflict only heightened the need for further communication and that the school should go ahead as planned, but with a special session devoted to discussion of the legitimacy of NATO's actions.

"Astronomy and Astrophysics Abstracts" appearing twice a year has become oneof the fundamental publications in the fields of astronomy, astrophysics andneighbouring sciences. It is the most important English-language abstracting journal in the mentioned branches. The abstracts are classified under more than a hundred subject categories, thus permitting a quick survey of the whole extended material. The AAA is a valuable and important publication for all students and scientists working in the fields of astronomy and related sciences. As such it represents a necessary ingredient of any astronomical library all over the world.