Jet and EtMiss Commissioning in ATLAS

A reliable reconstruction and calibration of jets and EtMiss in ATLAS is crucial to understand Standard Model Physics measurements and to discover new phenomena. This paper describes the step by step approach that ATLAS has adopted to reconstruct and calibrate jets and EtMiss to guarantee flexibility and robustness with first data. Main techniques are described to establish the energy scale "in-situ", which is the most challenging task for jets and EtMiss. Measuring jets and EtMiss is challenging but ATLAS has developped tools and strategies to be ready for commissioning with real collisions.