The Planning Commission during the Eleventh Plan made a significant departure from the past practice. Instead of relying on a single in-house model it was decided to request some of the reputed institutes in the field of economic model building to carry out modeling exercises that could be used not only for the purpose of plan formulation but also could answer some of the questions that arise from time to time such as the impact of rising oil prices on the performance of Indian economy, the impact of global meltdown, etc. The institutes that have worked in close coordination with the Planning Commission are the National Council of Applied Economic Research (NCAER), New Delhi, Institute of Economic Growth (IEG), Delhi, Indira Gandhi Institute of Development Research (IGIDR), Mumbai and Indian Statistical Institute (ISI), Bangalore. This volume contains essays by the relevant model builders reporting on the various models used in the course of formulating the Eleventh Plan and an overview paper by Dr. Kirit S. Parikh.