The results of theoretical and experimental investigations of heat and mass transfer enhancement on macro-, micro-, and nanoscale in single- and two-phase media, of phase interface vibrations, and of the separation of heterogeneous systems are presented. The research works carried out with the aim of increasing the safety and efficiency of power plants made it possible to develop new methods of heat and mass transfer intensification, formulate new research trends, to create new apparatuses, mathematical models of processes and the engineering methods of their calculations. Propulsion systems of spacecrafts for a piloted mission to Mars and the related methods of heat transfer intensification, the methods of calculation of heat and mass transfer under the conditions of scaling of twisted pipes and pipes with circular diaphragms, and the calculation of the hydrodynamics of multiphase heterogeneous media in a centrifugal field are considered additionally, as well as the results of the investigation into the influence of the roughened surface on heat transfer in boiling on a sphere and correlations of the data on the influence of tape twisting on the critical heat loading are presented. The results of comparing the characteristics of tubular and plate-type heat exchangers with heat transfer intensifiers, characteristics of heat transfer apparatuses with twisted tubes, as well as investigations of heat and mass transfer in condensation of steam from escaping flue gases of boilers are given. The book is intended for specialists involved in the development of power plants.