Foreword

In its first 50 years, X-ray astronomy has provided a new vision of the universe, with unsuspected high-energy activities at all scales.

In our Galaxy, a wide variety of systems - rapidly rotating Neutron Stars - remnants of Supernova explosions - compact objects (Neutron stars and Black Holes) accreting matter in binary systems - a Super Massive Black Hole lurking at the Galaxy’s centre - emit X-rays carrying fundamental information on their nature and origin.
On cosmological scales the intergalactic gas in clusters of galaxies shines at X-ray energies allowing to probe the gravitational field in these systems, related to the original seeds of structure in the Universe.

Supermassive Black Holes at the centers of galaxies, fed by the infall of gas, release extreme luminosities, that can be traced to very large distances, carrying information on the Universe evolution.

Understanding the physics of the X-ray Universe needs a step forward in observing capabilities, reaching fainter fluxes across large portions of sky and improving spectroscopy over a wide energy range possibly, time resolved.

The challenges for "the next 50 years" will be at the heart of the meeting. The conference will present a discussion of X-ray Astronomy today in order to envisage the most promising directions for future advances.