Introduction. Filtering and Control of Stochastic Systems. An Annual Nonlinear Model of the Indian Economy. Structural Analysis of the Model. Resolution and State Space Representation of the Model. Optimal Filtering and State Reconstruction. Optimal Control and Macroeconomic Planning. Conclusions. Appendices: A. The Optimum Linear Discrete Filter. B. The Discrete Maximum Principle. C. Controllability and Observability. Annexure: Data Used in the Estimation Process. References. Author and Subject Indexes.