Chapter 1 Generalities of gas diffusion applied to the vertebrate blood-gas barriers -- Chapter 2 Morphological and morphometric properties of the blood-gas barrier: comparative perspectives -- Chapter 3 Prenatal and postnatal development of the vertebrate blood-gas barrier -- Chapter 4 Molecular mechanisms regulating the pulmonary blood-gas barrier (BGB) -- Chapter 5 Barrier enhancing signals -- Chapter 6 Trans-barrier ion and fluid transport -- Chapter 7 Stress failure of the pulmonary blood-gas barrier -- Chapter 8 The lung endothelial barrier in acute inflammation -- Chapter 9 Lung transplantation and the blood-gas-barrier -- Chapter 10 Stereological studies on transient gas-exchangers, with emphasis on the structure and function of the human placenta in normal and compromised pregnancies.