EFL is a comprehensive language designed to make it easy to write portable, understandable programs. It provides a rich set of data types and structures, a convenient operator set, and good control flow forms. The lexical form is easy to type and to read. EFL was originated by A. D. Hall. The current author completed the design of the language and wrote the current compiler. Whenever possible, EFL uses the same forms that Ratfor [1] does; in this sense EFL may be viewed as a superset of Ratfor. EFL is a well-defined language; this distinguishes it from most “Fortran preprocessors” which only add simple flow of control constructs to Fortran.