In this paper I review the recent progress in understanding the physics of
the gas outflowing from active galactic nuclei and its impact on the
surrounding environment, using the combined information provided by
multiwavelength Ultraviolet-X-ray campaigns.Comment: 13 pages, 4 figures. Invited talk at the "High-resolution X-ray
spectroscopy: past, present, and future" conference, Utrecht, March 15-17
2010. Accepted for publication in Space Science Review