I love this kinda stuff.
As one faecinated by multiversi, I'm going to buy the issue for bedtime reading.

A great sci-fi book with this central theme is William Barton's ~1990 "The Transmigration of Souls". Ignore the title. A future America has retereated from its successful Return to the Moon and cuts itself from the rest of the world, insulated by its ultra high tech. The Arabs (main character) and Chinese mount rival moon missions to see what the Americans found and why they retreated in fear. Unfortunately for them, the Americans send their vastly superior hi tech military back to the moon to stop them. That's just the beginning.