A romance for teenage girls about the colonization of Mars (although some adult readers also like it). It's about ordinary people, not astronauts, and is especially recommended for readers who aren't especially enthusiastic about space--sometimes they, like the heroine, come to believe in the importance of settling new worlds. The 2006 edition, which has significant updating, should be read in preference to the 1970 edition, which will seem dated to today's teens.