I like the time-traveling effect I get when I read old cycling manuals - in particular, Reg Shaw's Let's Go Cycling from c.1950 is lovely, and in a perfect world would be paired with Cuthbertson's Anybody's Bike Book as introductory texts. Even more enjoyable, time-travel wise, is F.J. Camm's Every Cyclist's Handbook from 1936, which includes excellent directions for how to use Woods valves and maintain carbide headlights, and how to join two damaged inner tubes together to create one good one.
Put Me Back On My Bike by Tom Fotheringham left me with much more sympathy and understanding for Tom Simpson.
Across France in Wartime by Kuklos (1916?) also raised my eyebrows - how did a middle-aged English cyclotourist ride through a war zone on an X-frame Raleigh and get away with it?