The moon in question here is not the natural celestial object that has always been a feature of the night sky since the first time anyone took the trouble to look upwards.
No, the subject of Keep Watching the Skies! is the story of the worldwide effort - mainly by amateur astronomers, although it was suggested by Fred Whipple, a famous professional comet watcher - to monitor the artificial moon Sputnik 1 launched by the Soviet space programme.
I had always believed that the launch of Sputnik 1 on 4 October 1957 took the world by surprise. Sure, it was known that the US was working along similar lines and would attempt to put a man-made device into orbit as part of the 18-month programme, International Geophysical Year. But 84kg of electronics going "beep, beep, beep ..." every time it passed overhead at 90-minute intervals caught the powers that be with their metaphorical trousers round their ankles. So much so that the military panicked and rapidly paid up for Sir Bernard Lovell to complete the Jodrell Bank radio telescope to save our bacon from this diabolical new weapon.
Need they have bothered? Apparently not. All over the world amateur telescope enthusiasts were marshalling their forces for a gigantic effort to track the Earth's first travelling companion (sputnik in Russian means travelling companion) whenever it happened. Not only did optical devices not need monster receiving aerials but they would continue to give information concerning the whereabouts of spies, or worse, in the sky long after the objects' batteries ran out.
Sputnik 1 duly did stop transmitting on October of that year, but it continued its flight long after, constantly followed by the avid satellite spotters. And, what's more, they were soon to have a bigger and better new friend to howl about. The second satellite, Sputnik 2, carrying the Moscow stray dog, Laika, the first lady in space - she was a bitch! - caused a furore among dog lovers. This time the would-be observers were forewarned by no less an authority on space than the Daily Worker, which was expecting 5 November 1957 to be celebrated by an even bigger satellite. The Soviets obliged with more than 508kg of metal, which was clearly paving the way for humans to follow where an ill-fated mongrel had led.
The fireworks were saved for the US's first attempt to follow suit. In December 1957 a Vanguard rocket rose only a few feet from the launch pad before exploding. Its precious cargo did survive; it rolled across the site into the scrub. Operation Moonwatch was frustrated, as no telescope was needed to find it - it was still broadcasting to the world on a frequency of 108MHz. Flopnik, or America's worst debacle since Custer's last stand, were some of the more polite ways of describing this rather ignominious start to the space race.
By the middle of 1958 Moonwatch had grown to 230 teams with 8,000 active observers. At that point they stopped recruiting except from places where the coverage of the sky required was inadequate to get a precise fix on the seen but not heard satellites. Programmes such as Moonwatch have continued. I remember that in the 1970s the Science and Engineering Research Council, the previous incarnation of the Science and Technology Facilities Council, used to give a grant to Aston University to post out information about satellites that it wanted tracked. It was an early attempt to engage the public with science.
If you want to track satellites now, Keep Watching the Skies! is not for you - look on the web. This book is a superb history of what happened 50 years ago. For those with time on their hands, there are more than 2,500 working satellites and at least 5,000 more that have stopped sending signals back to their owners. For example, the US military recently shot down an errant Earth watcher. You don't even need a telescope nowadays; you can see things flying past with the naked eye. The best times are at dusk and just before dawn when they reflect the low-angle sunlight - the International Space Station is spectacular when it periodically crosses over Britain.
Keep Watching the Skies! The Story of Operation Moonwatch and the Dawn of the Space Age
By W. Patrick McCray. Princeton University Press 324pp, £17.95. ISBN 9780691128542. Published 1 May 2008