Gene Roddenberry sold "" in 1964 to NBC as a classic adventure drama, calling it a "Wagon Train to the Stars". But Roddenberry wanted to tell more sophisticated stories, using futuristic situations as analogies for current problems on Earth and showing how they could be rectified through humanism and optimism. The series' writers frequently addressed moral and social issues such as slavery, warfare, and discrimination. The opening line "to boldly go where no man has gone before" is almost from a U.S. White House booklet on space produced after the "Sputnik" flight in October 1957.