Library on Wheels-Mary Lemist Titcomb and America's First Bookmobile by Sharlee Glenn*

As Ms. Glenn, the author, was researching for a book about America's first library, she discovered a minute reference to Mary Titcomb.  Intrigued, she investigated this unknown pioneer of the bookmobile and decided to write a book about her instead!
Lots of photographs of the time period and from Ms. Titcomb's life adorn the pages.  Although very informative, the text is not too challenging and accessible to elementary readers.
The author even raised money for headstones of both Mary and her sister Lydia. 
*Highly recommend.
-Borrowed from the library.