I first saw this as a movie when it aired on television around 1975. At the time I didn't know there was a book. But if you're a fan of the space program, or simply like plausible but imaginative fiction, check this novel out. The idea of a kid sneaking aboard a NASA flight to the moon seems ridiculous on its face, but Shelton really delivers a credible story here. From beginning to end. Kids will love it and adults will appreciate the authenticity. Out of print but there seems to be several ex-library copies around. Really a nice book.