The story is fascinating from beginning to end. After listing all possible alternatives from Heinlein's stories, Wysocki analyzes naval technology of the time, providing a look at the details of radio and radar engineering that so engrossed SF readers and writers of the period. Along the way, we meet other SF writers, and learn, for example, what L. Sprague de Camp had to do with the evolution of the space suit. . . . When Wysocki reveals his answer (for which he presents good arguments), one feels a vague sense of letdown--not because of the answer, but because the book is over.