The Cambridge Handbook of English Historical Linguistics
by
Merja Kytö & Päivi Pahta (Editors)
See recommended resources for the Language Detective Assignment.
Highly Irregular: Why Tough, Through, and Dough Don't Rhyme - and Other Oddities of the English Language
by
Arika Okrent
Except after C: The Story of English Spelling
by
William Kottmeyer