West of the Moon

From the front flap of the first edition: This story tells how Mark and Meg Tremaine, two young people from Lower Earth, burst through a tunnel between universes, and find themselves West of the Moon in Middleworld - they grow up, are involved in war, magic, and a new form of space travel to the great living Moon of the Middleworld - and Mark at least is tempted to betray Middleworld. There is not just one universe, but three - stacked on above the other or one inside the other, in the dimension of distance from the One. Our universe is the outermost or lowest, and to the people of the world above, it is known as Hardol (Ironworld). And in magical Middleworld the most magical country is Vornemana, West of the Moon - a country threatened by war and deadly enemies lurking within.