Virtually all commercially important aromatic compounds in the modern world are produced by catalytic reforming of petroleum-derived naphtha. Some of these large-volume chemicals include benzene, toluene, xylene and ethyl benzene. These are further processed to produce intermediates such as styrene, cumene, phenol and Bisphenol A (BPA), and a variety of polymer products. Moreover, the stabilized reformate product is a valuable gasoline blending stock due to its superior octane boosting properties. The catalytic reformer occupies a key position in a refinery. The technology has even further impact in the refinery complex. The processes of hydrogenation, dehydrogenation, and isomerization have all benefited from the catalyst, reactor, and feed treatment technologies invented for catalytic reforming processes. We have attempted to provide an introduction to the topic of reforming written at a level such that researchers in different areas can obtain an appreciation of developments outside their present areas of expertise, and so that technical administrators and managers can obtain an overview of the subject.