You may want to get a quick overview of Duke history before you start on your work! The UA's website has a ton of historical information, including this brief history of Duke and this FAQs page.
These two books, though not exhaustive by any means, also provide quick and heavily-illustrated timelines of Duke history:
If you need something more in depth, these are the key secondary sources about Duke and Durham. They have great indexes, so they're easy to dip into when you need background on a historical person, issue, or event:
You'll notice that Professor Robert Durden's book ends in 1949--there isn't a secondary source on Duke history that covers 1950 to the present, although Jean Anderson's book will touch upon more recent major developments.
You can also check our Introduction to Duke University History research guide for even more information and pointers to UA collections!
Spend some time browsing through the materials--like Duke publications, photos, audio and video recordings, and more--that the University Archives has digitized.