For a brief few years between 1969 and 1972, astronauts walked the Moon. As odd it is to think of the space age as being so long in the past, even stranger is the idea that humans rather than robots were up there. But then it's hard to imagine a robot playing golf on the Moon, as Alan Shepard did. Only nine of those 12 moonwalkers are left to tell the tale.

But they not only ushered in the age of space, they also were the first global media celebrities. Six hundred million watched Buzz Aldrin and Neil Armstrong's first landing in 1969. But as we discover in Andrew Smith's poignant, often funny, eulogy to a seemingly more innocent age, many of these test pilots for the celebrity age eventually crashed and burned in alcohol, divorce and spiritual ennui.

The death of Apollo 12 astronaut Pete Conrad prompted Smith to go in search of the last nine living astronauts to find out what it was to experience the immensity of the universe and our infinitely small place in it. What was it like to walk on the Moon? What was life like afterwards? How do you top that? But with these alpha-male flyboys more accustomed to precision than introspection, getting them to articulate the profundity of these experiences forms a good deal of Smith's challenge.

Inevitably the words of the elusive Neil Armstrong echo through the book. Not just the eloquence of "one small step" but the plaintive outburst of "How long must it take before I cease to be known as a spaceman?" Conquering the colossal void of Armstrong's deep silence provides Smith with the narrative trajectory and the inevitable conclusion to the journey.

But in this respectful, compassionate book the author grapples with the nine differing non-PR trained personalities and comes to think of their inability to elucidate the experience as not simply a manifestation of shyness or arrogance or loathing of celebrity culture (or all of the above); Smith prefers to see it instead partly as maintaining the Moon's mystique. Partly too, Smith concedes that if NASA wanted poets, they would probably have sent poets. Mostly however it's the humanness that is the key to this story, though Smith's grand personal odyssey also ventures into the dark and cynical - conspiracy theories (dispelling the Hollywood hoax myth), political motivation (Kennedy's hope to submerge the Bay of Pigs in the Sea of Tranquillity) and Nazi legacy (behind the Saturn V rocket was V2-creator Werner von Braun's genius). But against this it is the vivid retelling of the struggle to succeed, and later to cope and overcome, which adds riveting human drama to the saga of man's first exploration of the Moon.