FWEB [5] is an implementation of Knuth's ``literate programming'' [6] concept which supports Fortran77 and Fortran90, et al.. ``Literate programming'' is basically Knuth's expression for self-documented code. There are three different parts of any given section of code: (1) a TeX(or LaTeX) part for commentary, (2) a definition part, and (3) a code part. Within FWEB it is possible through flags within commentary to turn on and off modes of documentation and code. The facilities fweave and ftangle build up TeX or LaTeX documentation from a given WEB file produce compilable code, respectively.