And that's exactly what the Moon was used as in the book, so men outnumbered women 2:1. Another prediction in the book is it's very easy to do heavy bombardment

And that's exactly what the Moon was used as in the book, so men outnumbered women 2:1. Another prediction in the book is it's very easy to do heavy bombardment of the Earth from there, using the Earth's gravity well, rail guns on the Moon, and lunar rocks. Next time I saw the Moon mentioned in a military context was in George Friedman's "The Next 100 Years", where he tries to predict what will happen throughout the rest of this century. The books gets very sci-fi towards the end, but it's a fun read. I wonder if Friedman has read Heinlein.