This book presents experimental data obtained by the author on hydrogen permeability, solubility and diffusion of hydrogen in aluminum and its alloys, as well as on porosity formation in aluminum and its alloys. The author offers new techniques for determining the surface tension of solid metals and the hydrogen content in aluminum alloys containing components with high vapour pressures. The book also considers the theory of porosity formation in metals. For the first time ever, the author presents a technique for metals and alloys treatment securing the removal of gases and eliminating gas unsoundness, known as the ‘hot isostatiс pressing technique’. The author proposes a technology, which ensures cutting down flaws caused by gas cavities in aluminum aircraft shell plates.