The physics of highly charged ions continues to be one of the most active and interesting fields of atomic physics. A large fraction of the characteristic radiation of such ions lies in the x-ray region and its spectroscopy represents an important experimental tool. The field of x-ray spectroscopy grew directly from the discovery of x radiation by Wilhelm Conrad Rontgen in 1895. The early contributions to atomic physics that arose out of x-ray spectroscopy are well documented and are the subject of many centennial events. In the past, the gross features of most x-ray spectra in the hard x-ray...