Book excerpt: Several new vacuum ultraviolet-emission continua recently observed in the spectra of the rare gases helium, argon, and xenon are discussed. These spectra were produced with a windowless light source operated as a repetitive condensed discharge and equipped with a differential pumping system to separate the high pressure (up to 800 mm Hg of helium) light source from the 2-m vacuum spectrograph (pressure 1/1000 mm Hg). In helium two continua were observed at pressures above 150 mm in addition to the weaker 600 to 950 angstroms continuum. The brightest extends from about 1050 to above 4000 angstroms and seems connected with greatly enhanced lines of He(II). The other continuum is the completely broadened principal series extending from 584 to about 510 angstroms and containing broadened principal series absorption lines. With argon in a flow system or xenon isolated with a LiF window, previously observed continua were extended from their resonance lines to beyond 3000 angstroms. Details of the experimental observations and possible explanations of these continua are presented. (Author).