Author/Editor appeared on the market in 1988 as the world's first specialized SGML editing application. The first version ran on the Macintosh. Windows and Unix versions followed in 1991. Author/Editor 3.0 was summarized as "a very pure structure editor which validates the document all the time. Documents which have a structure that doesn't comply with their document type definition can be edited by turning rules checking off, which can be helpful when re-arranging documents. The main window is a QUASIWYG representation of text, a structure view and a context view are also available. The structure view shows tags indented, the context view shows paths in the same way. An element list is used to pick up an element to insert. The representation on screen is done with a style editor, which generates style files. The program has many DTD with it, but new DTD's are imported by the RulesBuilder, which converts a DTD to a structure definition required by Author/Editor. There is an English thesaurus and a dictionary for spell checking."