Found this at a used book sale, and picked it up just so I could be depressed. :-)

This is a book about space travel that came out around 1968. (The version I have, however, is a slightly revised edition that takes into account the successful moon landing of 1969.) Clarke hits the subject of space travel from all angles, including rocketry, the physics of gravity wells, the physical limits of space travel, and the potential benefits. The depressing part, of course, is that from a 2013 perspective (which is when I read it) the actual progress we've made in space travel falls far short of the 1968 expectations.

Clarke writes with great knowledge and enthusiasm, and overall this is a pretty good book. ( )