Two-fluid dynamics is a challenging subject rich in interdisciplinary science. Reporting from the forefront of research in this area, these volumes combine scientific, engineering, and technological results in a sound mathematical framework. The analytical techniques used throughout the books are rigorously derived in Part I, Mathematic Theory and Applications, making the books appropriate for graduate study. Rotating flows of two liquids, the two-layer Bérnard problem, and plane channel flows are also thoroughly covered. In Part II, Lubricated Transport, Drops and Miscible Liquids, an extensive discussion of lubricated pipelining is given with the serious intention of advancing the technology. Core-annular flow, vortex rings in free fall, two-fluids with phase change, and miscible liquids are some of the topics presented in detail. Photographs, figures, graphs, and tables augment continuous comparison of theory and observations. These volumes are bound to become a standard source in a field which is attracting much scientific and industrial interest.