Space: the final frontier. Except it’s actually many frontiers. The history of spaceflight is fascinating precisely because of its incremental nature. Humanity didn’t suddenly venture forth into deep space, and obviously we have a ways to go yet. So I love reading about this history, and the Gemini program is something with which I was not very familiar. In Gemini: Stepping Stone to the Moon, the Untold Story, Jeffrey Kluger chronicles this program. I…