The Ranger's Apprentice -The Lost Stories by John Flanagan*

My eleven year old read this book to himself.
The book begins with professors and students at a dig in The Republic of Aralan States (formerly the medieval kingdom of Araluen) in July 1896.  Audrey, a young student volunteer, finds an outline of an ancient cabin.  Within the cabin, she and Professor MacFarlane discover the Lost Stories of Araluen.  The rest of the book contains 9 of those stories with an afterword circling back to MacFarlane and Audrey.
*Highy recommend.
-Borrowed from the library.
The library categorizes as "young adult".