Since the publication of the third edition of this book in 2011, a lot has
changed. Dramatic advances in mobile technology have resulted in the
unprecedented growth of social networks. This fast- changing technology land￾scape has forced me to make considerable changes to the contents of the book
to bring my faithful readers and students of information technology up to
date.
We have updated most of the contents in a good number of chapters,
added chapters with new contents and removed chapters with outdated con￾tent. With all these alterations, additions and removals, we have kept the core
theme of the text the same but brought new light, and new discussion points,
to the table. Although the book has been in production since 2002, when it
was selected as a Choice Outstanding Academic Title, the core theme of the
book has endured. This is a testimony not only to the quality of the bo