Introduction

Abstract

There is a long established tradition of Italian conferences on general relativity. That held in Bari in September 1998 was the 13th in a series of biennial events. Since the Italian Society of General Relativity and Gravitational Physics (SIGRAV) was founded in 1990, the biennial conference has been organized not only as a general scientific event but also as the official periodic meeting for the members of the Society. This contributes to the special features of this series of conferences which reflect the spirit and aims of SIGRAV, a scientific society of academics both from the mathematics and from the physics communities, both theoreticians and experimentalists, coming both from particle physics and from astrophysics and cosmology oriented institutes. The common ground for SIGRAV members is their interest in gravity and in time-honoured general relativity: the viewpoints on GR are very different but this is the special attraction of these conferences. Every year there are many specialized meetings instring theory, in experimental gravity, in cosmology and astrophysics, in gravitational wave detection and so on. Each of us goes to such meetings to hear about the specialized aspects of one’s field. The purpose of attending the biennial SIGRAV conference is different: there one seeks an overview, not of one’s own field, but rather of the other fields related to general relativity in which one is not a specialist. Indeed it is probably a unique feature of this surprising theory that it is still so much on the move after almost ninety years after its birth and that it is capable of uniting such a variety of scientific interests, applications and cultural backgrounds.