The Oxford History of Islam, edited by John L. Esposito
If you're looking for a scholarly one-volume history of Islam that is comprehensive, richly illustrated and designed to be readable, this is one of the best. The writers--men and women, Christian and Muslim--are among the finest scholars in their fields and display an enviable ability to select out of a vast ocean of material those events, people and ideas that make a particular topic lucid and understandable, especially for readers new to the field.