This examination of the microphysical processes which lead to cloud and precipitation formation emphasizes a quantitative description of the various mechanisms (e.g. nucleation, diffusional growth and evaporation, collisional growth and breakup) which lead to the formation of cloud and precipitation particles, individually and in populations. This edition has been updated to incorporate new research reported in a large number of articles and dozens of books and conference proceedings published since the first edition. Some highlights include: a new chapter on cloud chemistry; improved statistical mechanics models for homogeneous and heterogeneous ice nucleation; better data on aerosol size distribution and on fundamental properties of water; new data and models for asymmetric flow past particles of various shapes and for drop oscillation and breakup; extended treatment of drop coalescence and particle collision cross-sections, including some new effects of turbulence; more complete simulations of stochastic growth; expanded treatment of growth modes of graupel, rime and hailstones; new field data and modelling concerning effects of electric fields and charges on cloud microphysics.