Taking your reading with you has been a thing for a long time. Napoleon did it. Today, you don't need an e-reader to take your reading along or to have it come to you.
For the Love of Books: Mobile Libraries Around the World - Buses, shipping containers, donkeys, and...getting the books to the people. And, don't forget books-by-elephant!
10 Extraordinary Mobile Libraries - I guarantee won't believe some of these amazing moving libraries!
The Man Who Changed Reading Forever - The story of the revolutionary Venetian printer who shaped the world of modern portable books. Of related interest is Behold, the Kindle of the 16th Century, a story about the early attempts to make books easily accessible to a reader.
Jacobean Travelling Library, January 1617 - An example of a nobleman's travelling library.
Napoleon’s Kindle: The Miniaturized Traveling Library He Took on Military Campaigns - Not only did Napoleon have a traveling library, but what a library it was!
The Earliest Libraries-on-Wheels Looked Way Cooler Than Today's Bookmobiles - Photos of some pretty awesome early mobile libraries! See also this related story: A Brief History of Taking Books Along for the Ride.
Three Free Book Sites That Offer a World of Digital Books
The Harvard Classics - This is essentially the modern free digital version of books that an elite Western traveling library might have contained in the 19th and early 20th Centuries. Major literary figures, philosophers, religion, folklore and historical subjects.
Project Gutenberg - 60,000 free digitized books, including the world's great literature.
HathiTrust Digital Library - A not-for-profit collaborative of academic and research libraries preserving 17+ million digitized items, including thousands of freely available rare and hard-to-find books.