Okay, Littens, a mystery to solve that may, in fact, be unsolvable haha My husband remembers reading, in the late 70s, a series of scifi books that were probably for younger readers, but he may have actually stolen from the adult/YA section 😂 All he can remember is that they were about aliens on the moon who were going to blow up the earth and sent someone to reconnoiter and the books were this person going back & forth. Any thoughts???