This book gives an account, as little biased as possible, on human space missions beyond low Earth orbit in general, and specifically to the planets of the solar system. The importance of advanced propulsion is stressed and the mathematical methods needed to design missions based on them are described. The included computer code allows the user to assess the feasibility of the various missions using different propulsion systems and how advancements in propulsion can allow humankind to become a true spacefaring civilization.