Richard Preston's bestseller The Hot Zone told the story of the new plagues that threaten humankind. But his skill as a storyteller who makes documentary as gripping as a good novel was already known to astronomers, thanks to First Light. Never before published in Britain, and long out of print even in the US, it has been an underground classic among astronomers for 10 years, with dog-eared copies passed from hand to hand. Now it is in paperback for everyone to enjoy.

Apart from the fact that he is a superb writer, the secret of Preston's success is that he lives with his subjects for so long that he blends into the background, in this case a group of astronomers at Mount Palomar, California, in the Eighties, probing quasars at the edge of the visible universe. The result is not the best book written about astronomy - the science is a bit out of date, and some of the facts wrong. But it is the best book written about astronomers, and one of the best about the obsession that drives people to do this kind of work.

But the central character is the giant Hale Telescope itself, a monument to the ambition of Edwin Hubble, built largely during the Great Depression. In a sense, this was the last great achievement of 19th-century technology: a telescope a generation ahead of its time, which modern instruments are only now beginning to surpass. With its builders dead, nobody understands quite how it works. It is kept running by "gadgeteers" who beg surplus parts from rich institutions, rummage in refuse bins, and apply liberal quantities of sticky tape.

This entertaining book is not without its chilling moments, especially when Preston describes a breakneck ride across the Arizona desert, driven by Gene Shoemaker with his foot to the floor in an overloaded Plymouth Fury. A few months ago, Shoemaker, by then famous as co-discoverer of the comet that smashed into Jupiter in 1994, was killed in a crash while hunting meteor craters in Australia. In a way this fits the theme of the book, which contrasts the brevity of a human life with the immense ages of the objects that astronomers study.

First Light is the best book about science you are likely to find. And the best time to read it is in the depth of winter, when you can put it down, go outside, look at the night sky and imagine what the view must be like from Mount Palomar.