The internet changed all the rules by which business was conducted, more so, it changed everyone's life and that especially through the new way people can now interact. Nowadays, with the help of internet, we can virtually run any part of our business operation. We trade through e-business, we shop from e-mail, we pay our taxes through e-tax, we live in e-democracy and we are ruled by an e-government through e-governance. We live in a time when almost any human activity can be sent in an elctronic form. And only to exemplify this, we mention some of the e-activities like e-learning, e-sales, e-governance, e-commerce, e-management, e-marketing and e-banking. E-world, a series of ten books, is a humble effort to provide comprehensive learning and understanding of bassic concepts and applications of computers using internet. The books have been written keeping in mind the feedback received during the more than a decade of experience in teaching and interacting with the students and the practical knowledge gained during professional services. Interspersed with illustrations, tips and interesting facts, the concepts have been presented in a lucid and student-friendly manner useful for students, teachers, researchers, academicians and professionals.