Such causal narratives are unscientific because they can never be tested, Gee argues. We need to realise that the "fossil record" is nothing of the kind. All we have to go on are scattered remains preserved by chance: a few fossils that stand as "isolated tableaux illuminating the measureless corridor of deep time".The immensity of the geological time-scale over which life has evolved makes a nonsense of any attempt to construct scientific stories populated by ancestors, descendants and "missing links": "Deep Time is not a movie but a box of miscellaneous, unlabelled snapshots." Forget "meet the ancestors"; the most palaeontologists can aspire to is to discern degrees of relatedness, for all organisms are our cousins, close or distant.This insight forms the intellectual bedrock of cladistics, the classificatory scheme that has now become the orthodoxy among systematists. The goal is to create "cladograms" - branching diagrams that connect living things by their shared characteristics. Cladograms are not family trees, because they make no assertions of direct descent. Meeting the ancestors is acknowledged to be an impossible dream.Gee says this book "took much longer to write than I had imagined" and signs of the struggle seem just discernible.

Some chapters whiz along, notably "The Gang of Four", where Gee describes the summer studentship he spent ensconced in the fossil fish section of the Natural History Museum, which turned out to be the intellectual headquarters of cladistics in Britain. His account of lunchtimes spent with the gang in a seedy pub on the Old Brompton Road is a classic piece of reportage.He is excellent too at conveying the buzz that scientists feel every time a piece of original research knocks a dusty old textbook account off its perch. Gee says cladistics fosters such fresh thinking because it casts aside traditional preconceptions about functions or adaptation. So cladistically-minded researchers working on an early tetrapod fossil noticed that the thing has eight digits, when previous workers stopped looking when they reached the expected five. Colleagues found fossil dinosaurs sprouting feathers that had nothing to do with flying.There are times when Gee seems to overstate his case. You want to ask the forbidden question, "If feathers did not evolve for flight, what did they evolve for?" Gee is stern: "As we now know, such questions about adaptive purpose are unanswerable."As he reiterates, the living creatures fossils once were are long gone, so we can never know much about what life was like for them. Still, isn't it interesting, even legitimate, to speculate that the feather-like things on some dinosaurs could have provided thermal insulation or been used for sexual display? Can palaeontology do without such imaginings?A few years ago, even Nature called a new human-like fossil a "missing link" in its press release.

At the time, writes a contrite Gee, it "seemed a more digestible substitute for phrases such as 'the hominid-closest-to-the-evolutionary-split-between-our-lineage-and-that-of the-apes'." The Daily Express gave the story upbeat coverage. It recast the fossil as Fred Flintstone's honoured ancestor, under the headline "Yabba Dabba Doo!" It's no contest when cladistics meets the comics. But both Tudge and Gee deserve high praise for these stimulating additions to the popular-science canon.. Desmond Barry confesses that the Pogues ballad about the legendary American outlaw inspired him to write a voice for Jesse James, that "dirty little coward who shot Mr Howard", in his gritty first novel The Chivalry of Crime. The researcher for Peter Carey's novel Jack Maggs, Barry shows an extraordinary talent for creating historical characters who inhabit a convincing past.

James is scarcely likeable, but his motives become understandable, and so does his significant place in the American psyche. This is a great, galloping, delightful read that will rope in even readers who are no fans of the Western. Desmond Barry confesses that the Pogues ballad about the legendary American outlaw inspired him to write a voice for Jesse James, that "dirty little coward who shot Mr Howard", in his gritty first novel The Chivalry of Crime. The researcher for Peter Carey's novel Jack Maggs, Barry shows an extraordinary talent for creating historical characters who inhabit a convincing past. James is scarcely likeable, but his motives become understandable, and so does his significant place in the American psyche. This is a great, galloping, delightful read that will rope in even readers who are no fans of the Western. Barry gives this novel depth by making the historical link between the Confederate rebels who operated like a guerrilla army (chillingly reminiscent of the Bosnian Serbs) during the American civil war, and the legendary outlaws of the West. He mines the seam of violence that underpinned US political development and reveals how intimately it was bound up with nascent ideologies.Jesse joins his brother, hiding out with the rebels after a Union officer tortures him and his stepfather at their family farm in Missouri for information that would lead them to the "guerrillas".