Hermann Julius Oberth was an Austro-Hungarian-born German physicist and engineer. He is considered one of the founding fathers of rocketry and astronautics.
Herman Oberth is one of the main fathers of rocketry. It was published years before any man rode a rocket into space. He goes in details on how to send men into space, Moon cars, and even space stations. He even disagrees with Van Braun on some tactics. It's a very interesting book on early space age technology and history.