This volume presents a broad comparative anatomical approach towards the functional morphology of the middle ear of palaeognathous birds (ostrich, rhea, tinamous, emu, cassowary, kiwi) and basal neognathous birds. It presents the most complete and thoroughly studied source of material on this field. For the first time it became possible to develop exact images of "non-structures" like the air-filled spaces of the avian skull by using non-invasive CT-techniques, computer-aided 3D-reconstruction, and morphometry, and to evaluate their functional importance for sound transmission and amplification through the middle ear. A series of air brush drawings represent detailed three-dimensional images of middle ear structures and the pneumatic spaces of the octic region of the skull.