It is difficult to evaluate an organization's performance when there are multiple inputs and multiple outputs to the system. The difficulties are further enhanced when the relationships between the inputs and the outputs are complex and involve unknown tradeoffs. This work introduces DEA as a multiple-measure performance evaluation and benchmarking tool. The focus of performance evaluation and benchmarking is shifted from characterizing performance in terms of single measures to evaluating performance as a multidimensional systems perspective. New DEA models and approaches are presented to deal with performance evaluation problems in a variety of contexts. A context-dependent DEA measures the relative attractiveness of similar operations/processes/products. Sensitivity analysis techniques can be easily applied and used to identify critical performance measures. Value chain efficiency models and DEA benchmarking models can be utilized to study the impact of information technology (IT) investments. These models can help organizations better understand the real impact of their IT investments and integrate technology more efficiently and effectively for the future. Conventional and new DEA approaches are presented and discussed using spreadsheets - one of the most effective ways to analyse and evaluate decision alternatives. The user can easily develop and customize new DEA models based upon these spreadsheets. This book also provides easy-to- use DEA software - DEA Excel Solver. This DEA Excel Solver is an Add-In for Microsoft Excel and provides a custom menu of DEA approaches, which include more than 150 different DEA models. It is a powerful tool that can assist decision-makers in benchmarking and analysing complex operational efficiency issues in manufacturing organizations as well as evaluating processes in banking, retail, franchising, health care, e- business, public services and many other industries. The DEA Excel Solver does not set limit on the number of unit