In a competitive environment most of the business firms face an irritatingly limited supply of resources. This has led to a significant emphasis on the efficient utilization of their resources. This present monograph discusses the uses of various variants of data envelopment analysis (DEA) models for evaluating firm efficiency in different industries. In this volume, we first contrast both frontier translog production function and DEA for estimating returns to scale and efficiencies by applying them to data on Indian Steel industry. Second, we use DEA to estimate the technical efficiency of a number of firms in the Indian pig and sponge iron industry. The methods of cross-efficiency matrix, distribution of virtual inputs, and returns to scale are also used to get further insights. Third, DEA is applied to 28 Indian Sunrise Industries to measure their technical progress. The method is further used to find out the lagging and/or surpassing periods, which reflect their change in technical efficiency. Finally, DEA is used to decompose productivity growth of the Indian Sunrise Industries into technical change, efficiency change, and scale change.