Joel Carmichael 
The Shaping of the Arabs [PDF ebook] 
A Study in Ethnic Identity

This book, first published in 1969, brings out clearly and concisely the complex moulding of Arab identity. The present-day Arabic-speaking peoples may be traced back to the Arabian tribes that were later to be shaped into a people by Islam. With the Muslim conquests the language of the Arabian tribes became the vernacular of a vast cosmopolitan society extending throughout the Middle East and Southern Mediterranean.