SciFi YA - The rollicking adventures of the Stone Family on a tour of the Solar System. It all started when the twins, Castor and Pollux Stone, decided that life on the Lunar colony was too dull and decided to buy their own spaceship and go into business for themselves. Their father thought that was a fine idea, except that he and Grandma Hazel bought the spaceship and the whole Stone Family were on their way out into the far reaches of the Solar System, with stops on Mars (where the twins got a lesson in the interplanetary economics of bicycles and the adorable little critters called flatcats who, it turned out, bred like rabbits; or perhaps, Tribbles....), out to the asteroids, where Mrs. Stone, an M.D., was needed to treat a dangerous outbreak of disease, even further out, to Titan and beyond.
Robert Anson Heinlein was an American science fiction writer. Often called "the dean of science fiction writers", he was one of the most popular, influential, and controversial authors of the genre. He set a high standard for science and engineering plausibility and helped to raise the genre's standards of literary quality. He was one of the first writers to break into mainstream, general magazines such as The Saturday Evening Post, in the late 1940s, with unvarnished science fiction. He was among the first authors of bestselling, novel-length science fiction in the modern, mass-market era. For many years, Heinlein, Isaac Asimov, and Arthur C. Clarke were known as the "Big Three" of science fiction. ([Source](http://en.wikipedia.org/wiki/Robert_A._Heinlein).)
