X-ray astronomy in cosmology and astrophysics: From eROSITA to the future.

This year marks the 60th anniversary of the birth of X-ray astronomy. Since the discovery of X-rays from, at the time mysterious, celestial source Sco X-1, the discipline's contribution to the understanding of the astrophysical Universe and of cosmology has been enormous. In the first part of my communication, I will attempt to summarise the fundamental contributions of X-ray astronomy and astrophysics to the advancement of the study of the Universe, in conjunction with the achievements of the larger field of high-energy astrophysics. I will then summarise the scientific and technological aspects of the German eROSITA mission, on board the Spectrum X-Gamma satellite. I will also discuss some of the most significant highlights of the mission. In the third part of my contribution, I will take a look at the future of X-astronomy, discussing future missions, the scientific cases driving their development, and the challenging, new frontier of X-ray interferometry.