I've been seriously considering writing a book on the origins of the English language. I'd like to start the book with information about the british Isles prior to the arrival of the anglo saxons, actually beginning with the first people to set foot upon the land. I'm finding this information somewhat difficult to find. Could anyone direct me to some sources of information on this subject? Or just give me a summary of human occupation of the Isles up to the arrival of the anglo saxons?