Electrical impedance tomography for the first time provides a bedside method for the non-invasive, reliable determination of regional lung function without radiation exposure. In contrast to other medical im¬aging methods, EIT displays body functions instead of body structures. The real-time images as well as the EIT-based special lung function parameters support clinicians with the regular evaluation of the vari¬able pulmonary status in order to adjust the ventilation to individual patient needs. Electrical impedance tomography, in turn, supports the implementation of lung-protective ventilation, therapeutic positioning, and weaning. This second edition was published to help you, dear readers, with the interpretation of complex EIT data. Using simple decision flowcharts, the description guides the reader gradually and understandably through the assessment of functional imaging, while discussing possible caus¬es for the respective findings and appropriate therapeutic measures. A variety of illustrations and supplementary information were added to further enhance understanding.