This book summarizes results on the creation of a new theory of condensation which has an impact on consideration of some microscopic effects left aside in the usual nucleation theories. In particular, the main idea of the authors' microscopic condensation theory is that it considers the violation of the equilibrium cluster distribution over the internal degrees of freedom due to co-occurring condensation and decay reactions of the clusters.Contents:Brief Review of the Existing Nucleation TheoriesMain Principles of the Microscopic Theory of CondensationJuxtaposition with the Other Theories and ExperimentsKinetic Theory of Photostimulated NucleationKinetic Theory of Iron-Induced NucleationConclusionsAppendices: Dimensionless Form of SystemLow-Pressure LimitQuasisteady Equations for ConcentrationsFORTRAN Subroutines for Computing Parameters of the TheoryReadership: Applied mathematicians, physicists, chemists and aeronomers.Key Features:It is the latest collection of recent resultsThe areas covered are not presented in any other competitive titleMost of the contributors (authors) are well-known specialists in the fieldAll papers contain new experimental and/or theoretical results