In September 1967, I started working at NASA in Houston, at what was then called the Manned Spacecraft Center. I worked on Apollo missions. In November 1971, I left NASA and moved to Denver to work on the Viking Mars lander project at Martin Marietta Corporation.By the time I left NASA, Apollo was winding down. Manned spaceflight beyond Earth orbit was dying. There would be no lunar bases or missions to Mars. In a mere four years, the future had died. Fifty years later, I still can't shake the sadness.Of course the "We" in the title of this book is not literal. Only the handful of men who have actually been on the moon can talk about "when we landed on the moon" and mean it literally. I'm using "we" in a general sense, to refer to all of the 400,000 people who worked on the Apollo Project, to all of America, and to the entire human race.As the plaque on the side of the Apollo 11 Lunar Module descent stage, which still stands on the moon's Sea of Tranquility, proclaims: "Here men from the planet Earth first set foot upon the Moon, July 1969 A.D. We came in peace for all mankind."This is the story of my part in Apollo.