The Linear Production Model: A General and Simple Approach Antonio Villar University of Alicante & Ivie A b st r act This paper presents a very general linear production model which nevert heless shows an ext remely regular behaviour. We can ensure t he solvability of the associated equilibrium systems for quantities and prices and the nonsubstitution property, allowing for joint produc- t ion and non-square syst ems. The assumptions we use are intuitive and very mild (e.g. they are necessary for the type of solvability we require). Proofs are simple and rely on geometrical arguments (the separation theorems), rather than on the use of the theory of deter- minant s. JEL classi…cati on number s: C67, D57. K eywords: Input-output analysis; Joint Production; Non-Substitution T heorem. Address for cor respondence: Antonio Villar, Deparment of Economics, University of Alicante, 03080 Alicante, Spain. E-mail: Villar@merlin.fae.ua.es 1