Bloody Foreigners: The Story of Immigration to Britain by Robert Winder
This was a summer holiday book that I just read. It was thought provoking and readable. The first parts of the book dealt with the familiar stories of Jewish and Huguenot migration.
The real meat of the book dealt with the 20th century and particularly post second world war. It ranged over big picture topics such as racism, economics, islamophobia etc… Also how the topic can be taken over by populist politicians (who are often descended from immigrants anyway).