Our book today is This Thing of Darkness, a whopping-long 2005 historical novel by Harry Thompson about the fateful voyage of the HMS Beagle to Tierra del Fuego in 1828. The ship was captained by 23-year-old Robert FitzRoy, and of course its most famous passenger was the young amateur naturalist Charles Darwin. But Thompson’s novel differs fascinatingly from its only main predecessor, Irving Stone’s 1980 monolith The Origin in that it’s FitzRoy and not Darwin who holds the spotlight at the hero of the plot – no mean trick, especially in light of the one thing most general readers know about FitzRoy, which is that late in his life he Bible-wavingly protested his part in germinating Darwin’s world-changing book on the origin of species.

That FitzRoy – much older, much more bitter and confused – bears no resemblance to the brilliant, self-doubting martinet of Thompson’s novel, a young captain with immense force of will who’s as hard on himself as he is on the men under his command. Thompson makes the superb tactical decision of giving us FitzRoy’s adventures aboard the Beagle for a full 200 pages (alone the length of most full novels) before Darwin makes his first appearance. It’s during this first part of the book that we see Thompson’s wonderful realization of a FitzRoy whose later ground-breaking fascination with the workings of weather are only just being born of a tragedy that cost two of his men their lives – a fact for which the young captain can’t forgive himself:

‘Every experienced captain knows where to find a fair wind or favourable current. Do you think the winds blow at random? Those two poor souls who died yesterday – was that God’s punishment or the result of my blunder?’

‘I know it was God’s will.’

‘Mr Sullivan, if God created this world to a purpose, would He have left the winds and currents to chance? What if the weather is actually a gigantic machine created by God? What if the whole of creation is ordered and comprehensible? What if we could analyse how His machine works and foretell its every move? No one need ever die in a storm again.’

‘It is too fantastical an idea.’

It’s not as fantastical an idea as the one that will take shape in the mind of his new onboard naturalist in due time, although even FitzRoy, when confronted with the mulish, offhand racism of his crew, can defend angrily enough the idea that living creatures can adapt and change over time, as when he upbraids a crewman for his dismissive attitude toward the natives of Tierra del Fuego:

‘They most certainly are men, just as you or I. Unfortunate men, maybe, forced by accident of circumstance to inhabit this Godforsaken spot, but they are our brothers nonetheless. They do not look like us because their physiognomy has adapted itself to the cold and the rain. Were I to cast you ashore, Mr King, and were the good Lord to take pity on your soul and spare your life, then within a generation or two your progeny would very likely be short, plump and jabbering away like the lowliest Fuegian.’

‘But it doesn’t mean anything – does it, sir? Those noises they make?’

‘How do you know? To the best of my knowledge, no Dr Johnson has ever taken the trouble to compile a dictionary of their language. An omission I intend to remedy personally. Instead of waving a loaded gun about the maindeck, Mr King, you would be better advised to improve your intelligence of such matters. I suggest you consult the scriptures, commencing with the Book of Genesis.’

By the time the book reaches its long second part, we’re primed for the famous meeting of the two men, and Thompson doesn’t disappoint, underscoring the encounter with light irony:

The stranger was extremely tall – at least six feet in height, thickset and shambling, with long arms, a pleasant round face and friendly grey eyes. His bulbous unsightly nose was squashed against his face like that of a farmer recently defeated in a tavern brawl. All in all, it struck FitzRoy that there was something vaguely simian about the young man’s appearance.

Despite their radical differences in personality and outlook, the two men become fast friends in short order (although he always cited more arcane sources, Patrick O’Brian simply had to have had this relationship in mind when creating Jack Aubrey and Stephen Maturin) – but the seeds of their future estrangement were never far from the surface, especially on the subject of Biblical inerrancy, a subject about which Darwin, the clerical “trainee” (as Thompson calls him), was well-equipped to debate his pious captain:

‘Come, come, my dear FitzRoy, you know as well as I that the scriptures are contradictory. In Genesis one, twenty-four, the Lord brings forth all living creatures before He maketh man on the sixth day, having already created fish and fowl on the fifth day. What if, as de Luc contends, these “days” were not days as we know them but great ages, epochs lasting many thousands of years? What if man never encountered these monstrous beasts?’

This Thing of Darkness was long-listed for the Man Booker Prize in 2005 (it lost to the entirely inferior The Sea by John Banville), and Harry Thompson also died in 2005, of lung cancer at the age of 45, after a blazingly innovative and uproarious career writing and producing British television. This enormous and prodigious book was his only novel, a thing he’d worked on more or less steadily for the bulk of his adult life – and into which he poured almost every scrap of his wide-ranging reading and near-perfect gift for dialogue. He never intended this book to be a memorial, but it makes a damn impressive one just the same.