The Motor Girls on Waters Blue; or, The Strange Cruise of the Tartar (Esprios Classics) - Margaret Penrose Book

Margaret Penrose was a house pseudonym used by the Stratemeyer Syndicate. The name Margaret Penrose was used for: The Dorothy Dale series, The Radio Girls series (Later reprinted as The Campfire Girls series) and The Motor Girls series. The Stratemeyer Syndicate was a publishing company that produced a number of mystery book series for children, including Nancy Drew, the Hardy Boys, the various Tom Swift series, the Bobbsey Twins, the Rover Boys, and others. They published and contracted the many pseudonymous authors doing the writing of the series from 1899 through 1987, when the syndicate partners sold the company to Mega-Books.