Webster, Rachel L.Drinkwater, Michael J.Francis, PaulMasci, Frank J.Peterson, Bruce A.2018-09-21978-3-662-22488-51431-2433http://hdl.handle.net/1885/147748Quasars provide a unique probe of the matter distribution along high red-shift lines-of-sight, both through absorption line and gravitational lens studies. However if the selection of quasars is biased, then the related statistical descriptions of the matter distribution may also be biased. Recent work on a completely identified sample of radio sources shows that many quasars are significantly reddened. Arguments are presented which favour dust as the explanation of the reddening. Possible locations for the dust are explored, and the consequences of biased quasar selection briefly discussed.application/pdf© Springer-Verlag Berlin Heidelberg 1997Radio SourceActive Galactic NucleusEquivalent WidthRadio GalaxyHost Galaxy199710.1007/978-3-540-49709-7_41