This book follows the tradition of the previous editions by incorporating emerging trends in mobile computing and commerce, it virtualization, social media, cloud computing and management and analysis of big data along with advances in more established areas of information Technology. More templates, reference models and graphics have been added to make learning more appealing to senses, which enhance learner content engagement and retention. This edition has been adapted for Indian learners. Learners appreciate application of concepts in Global as well as local context. Local context has been factored through localized cases, exercises and examples in both private and public domain. The extent of adaptation has been balanced to retain its global flavour.