I have about twenty books that I am using to research Road from the West, and about half a dozen of those I refer to regularly. One of my most important titles is The Gesta Tancredi of Ralph of Caen: A History of the Normans on the First Crusade (Crusade Texts in Translation). Medieval texts can be pricey and this one currently retails for one hundred dollars on Amazon.
The other day Oliver threw up all over this book. A lot. True story.
I still think he's cute.