In this book attempts have been made to discuss the real life phenomena related to occupational mobility, manpower planning, undocumented migration and diffusion of rumours within a cluster and among several clusters through different probability models in six different chapters. Some mobility measures are described with real life data. Presented stochastic models are verified through simulation studies. This book is written in such a way that readers who are moderately knowledgeable in stochastic process can understand the subject well. This book will be of use to students, researchers and teachers interested in stochastic modelling of social research.