These case studies highlight the field of linear programming (LP) from two perspectives, an application and an algorithm. The Diet Problem, dating back to the 1930s and the 1940s, presents a LP model for selecting a minimum cost set of foods that will satisfy a set of daily nutritional requirements. The case study includes an interactive tool for building a menu. Developed by George Dantzig, the simplex method is an efficient procedure for solving LP problems. The Simplex Method Tools provide an interactive framework for stepping through the iterations of the simplex method.