Behold, the hundreds of free e-books about space history contained on this webpage.
From old favorites like The Difficult Road to Mars: A Brief History of Mars Exploration in the Soviet Union and Wind Tunnels of NASA to experimental work like Aerospace Food Technology and Life in the Universe: Proceedings of a conference held at NASA Ames Research Center Moffet Field, California, June 19-20, 1979, this is one of the best collections of space arcana you're likely to find.
These books were placed online over the last decade, so some of the formatting leaves something to be desired. Many of the works have been broken up into tiny pieces, forcing one to click through page after page. But this is a singular information repository, a storehouse for our fascination with flight.