The purpose of the School is to familiarize students with the status of the R&D activities in the areas of ADS for energy production and transmutation. A review of the ADS designs presently under consideration will be given. Participants will study the theoretical foundations of all the ADS design aspects (i.e. high-power accelerator, spallation target and sub-critical core) and identify the most problematic areas, as well as the limitations of the simulation methods presently used. Students will familiarize with the modern theoretical models used to predict nuclear reaction cross sections. They will study the principles of the evaluation methodology and become acquainted with the existing data libraries and the data processing and transport calculations. Based on the discussion of the impact of the present uncertainties on the performance of the ADS, the needs for data and methods development and validation work will be identified. The School will consist of lectures, computer demonstrations, tutorials and exercise sessions. Participants will also be invited to make short (15 minutes) presentations of their own research activity.