This book contains 17 studies by leading international scholars working on a wide range of topics in Arabic socio-linguistics, divided into four parts. The studies in Part 1 address questions of national language planning in a diglossic situation, with a particular focus on North Africa. Part 2 explores the relationship of identity and language choice in different Arabic-speaking communities living both within and outside the Arab World. Part 3 examines language choice in such diverse contexts as popular preaching, humour and Arab women's writing. Part 4 contains 5 papers in which variation, code-switching and generational language shift in the Arabic-language diaspora in Europe and the USA are the focus. The collection as a whole provides wide-ranging introduction to key areas of current research, which will be of interest to the general sociolinguist as well as the Arabic language specialist.