This is the start of a long process to ultimately operate new advanced capabilities at Paranal that can keep up with the evergrowing need for larger and more complex astrophysical data sets. A modern instrument represents a very significant investment in cash, human resources and time. Such a meeting gives us a precious yardstick to evaluate the competitiveness of 1st-generation instruments and associated current and forthcoming proposals for 1st-generation upgrades. This is also crucial to orient the large research and development effort that will provide the very foundation on which 2nd-generation VLT instrumentation can be built. Finally, it represents a significant step towards defining the hopes and goals for the future Extremely Large Telescope to come. The first outcome of this meeting, already in progress, is outlined in the epilogue.

NASA’s James Webb Space Telescope (JWST), planned for operation in about five years, will have the capability to investigate – and answer – some of the most challenging questions in astronomy. Although motivated and designed to study the very early Universe, the performance of the observatory’s instruments over a very wide wavelength range will allow the world’s scientific community unequaled ability to study cosmic phenomena as diverse as small bodies in the Solar System and the formation of galaxies. As part of preparation to use JWST, a conference was held in Tucson, Arizona in 2007 that brought together astronomers from around the world to discuss the mission, other major facilities that will operate in the coming decade, and major scientific goals for them. This book is a compilation of those presentations by some of the leading researchers from all branches of astronomy. This book also includes a “pre-history” of JWST, describing the lengthy process and some of the key individuals that initiated early work on the concepts that would evolve to become the premier space observatory of the next decade.

E. KONTIZAS Astronomical Institute National Observatory of Athens P. O. Box 20048 Athens GR-1181O GREECE The international conference on "Wide-Field Spectroscopy" and its sub ject matter were agreed during the general assembly of the International Astronomical Union (IAU) in August 1994 by the Working Group of Com mision 9 "Wi de-Field Imaging". This meeting gave an opportunity to world experts on this subject to gather in Athens, in order to discuss the cur rent exploitation and the impending opportunities that exist in the area of multi-object spectroscopy, with particular emphasis on: 1. Astronomical instruments, data acquisition, processing and analysis techniques. 2. Astrophysical problems best tackled through wide-field, multi-object spectroscopy. The new fibre optic technology offers an important tool for the advancement of basic research and the development of industrial applications. Astronom ical spectroscopy is a field of astronomy which has contributed much to the advancement of fundamental physics. The spectra of hot stars have been used to determine the well-known Balmer formula for the wavelength of hydrogen lines, in the late 19th century. Since then, spectroscopy has made enormous progress in stellar atmosphere studies, in kinematics, and in the detection of high redshifts in the Universe. The traditional techniques of obtaining wide-field spectroscopic data are based on slitless spectroscopy (objective prism). Several observations, world wide, make use ofthese tech niques in order to obtain information on the spectral properties of objects in large areas of the sky.

The paradigm of a dark energy- and dark matter-dominated Universe, with the hierarchical merger scenario for the formation of galaxies, has scored impressive successes in matching the observed Universe. However, the theory fails to explain the difficulty in generating ordinary disk galaxies such as the Milky Way, suggesting that some important physics must be missing in current models. IAU Symposium 254 was organized to address this question, gathering researchers from an unusually broad range of fields, from cosmology to interstellar matter, and the formation and evolution of stars. High-class reviews, lectures and posters combine to define the frontiers in the field and point the way to new avenues of research. This volume presents a unique set of succinct overviews illuminating the full range of topics in this very active field. It also honors Danish astrophysicist Bengt Strömgren (1908-1987), who laid much of the foundation for this entire field.

Session I : Primordial nucleosynthesis and the first stars in the Universe -- Session II : First stars in the Galaxy -- Session III : Chemical abundances in the high red-shift Universe -- Session IV : Chemical abundance constraints on mass assembly and star formation in local galaxies and the Milky Way -- Session V : Extrasolar planets: the chemical abundance connection -- Session VI : Abundance surveys and projects in the era of future large telescopes.