Fresh from college, the author gets a job at the MIT lab that created the Apollo guidance system. His assignment is to program the complex lunar landing phase of the mission. As he masters his art the reader learns about the computer, the mission, and a bit about spacecraft navigation — and meets a cast of brilliant characters along the way. As Apollo 11 approaches, the author flies lunar descents in simulators and meets the astronauts who will fly the LM for real. He explains the computer alarms that almost prevented Neil Armstrong from landing — and describes a narrow escape from another dangerous problem. He helps Pete Conrad achieve a pinpoint landing on Apollo 12, and works with Apollo 16 commander John Young on a technique for landing even more precisely. On Apollo 14 he devises a workaround when a faulty pushbutton threatens Alan Shepard’s mission, earning a NASA award, a story in Rolling Stone, and a few lines in the history books. Along the way the author hits the high points of his eclectic personal life, as he enters adulthood in the 1960s. He writes for students of the Apollo project, for whom the development of the flight software is still largely unexplored territory, but also for the young coders of the contemporary digital culture, who will resonate with his insights into the art of programming — and who will identify with him as he explores sex, drugs, and the other excitements of the era. The underlying thesis is that the American space program in the 1960s was successful not in spite of, but in large measure because of the idealism, the freedom of thought, and the sense of exploration, inner and outer, that prevailed in the culture during that period. The memoir concludes in a party atmosphere at the spectacular night launch of Apollo 17 before a glittery crowd — an occasion that marked the high water mark, so far, of human space exploration.