This report documents a package of computer programs called VENVAL. These programs prepare plywood mill data for a linear programming (LP) model that, in turn, calculates the optimum mix of products to make, given a set of technologies and market prices. (The software to solve a linear program is not provided and must be obtained separately.) Linear programming finds the best solutions for a given set of circumstances. This paper illustrates and describes the software programs of VENVAL and its use in LP for softwood plywood mill operations.