Two families of mathematical models for the kinetics of granule nucleation are presented. The first assumes that the driving force is surface tension at the three-phase interface and that this process is retarded by viscous drag. The second model assumes that transport within the nucleus occurs as a consequence of continual small deformations giving rise to a diffusive-type flow. For both of these models planar and spherical geometries are considered. In all cases explicit analytical expressions are deduced, of varying degrees of approximation, enabling their use in a multi-scale description of the granulation process. The models reveal the scaling rules for nucleation and suggest a series of experiments for their verification. (C) 2008 Elsevier B.V. All rights reserved.