We describe an integral approach to the rigorous solution of Maxwell's equations for diffraction from a biperiodic grating having arbitrary profile and periodicity. Emphasis is placed on the implementation of solutions and is addressed to the engineering community. The method described is amenable to mathematical convergence analysis. A numerical example is given which indicates convergence of solutions.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.