It is a commonplace that human knowledge has expanded far beyond the capacity of a single human mind to contain all of it, so much so that no individual now would consider making the attempt. But such was not always the case. When information about the world was less bewilderingly extensive, the endeavour to synthesise it was undertaken from time to time, and some of these efforts are of great value to us even today – consider the writings of Aristotle on everything from literary criticism to fish. We also think of Pliny (the Elder) in Rome; of Leonardo, the universal man, in the High Renaissance; and, more obscurely perhaps, someone like the 17th-century Jesuit polymath Athanasius Kircher.

But who was the last? Who was the last before it became impossible, before learning swelled so monstrously that specialisation became de rigueur – the last person who was interested in everything (more or less) and deeply knowledgeable about it all? A good case can be made that it was Alexander von Humboldt, the German naturalist and explorer and contemporary of Napoleon, and a riveting new biography of him makes it with panache.

Who? You may well ask. Andrea Wulf has anticipated your reaction. She told a meeting of the Royal Geographical Society earlier this year that when she informed her English friends – she is an Anglophone German – that she was embarking upon a life of Humboldt, she was met almost universally with blank faces, and it is one of her principal themes, and a subsidiary title of the book, that her subject is The Lost Hero of Science.

Certainly in the English-speaking world Humboldt is largely forgotten outside academia, yet he was once the most famous man on the planet besides his contemporary, Bonaparte, and he has had more organisms named after him than anyone else – nearly 300 plants and more than 100 animals – not to mention dozens of monuments, parks, mountains and other natural features, including a geyser, a bay, a cape and a glacier as well as a famous ocean current, and in North America alone four counties and 13 towns.

The begetter of this fantastical legacy was born into the high aristocracy of Frederick the Great’s Prussia in 1769. Humboldt was an archetypal product of the age of the enlightened despots, perhaps the most glittering one; indeed, you might say he was the Enlightenment’s golden child. Such was his hunger for knowledge of the sciences and the natural world, and his rapid acquisition of it, and his astounding fluency in conversing of it, that by his mid-twenties he had conquered the scientific-minded German literary establishment led by Goethe and Schiller, who regarded him as some kind of wunderkind (with his good breeding helping, naturally.) But a larger stage than the salons of Weimar and Jena awaited him.

In 1799 he embarked, with a French companion, Aimé Bonpland, on a five-year scientific exploration of the Americas, which made him internationally famous. Humboldt’s flamboyant accounts of their hair-raising adventures in the jungles and the mountains of Venezuela, Colombia, Ecuador, Peru and Mexico, his tales of scaling unclimbed volcanoes and testing the shock of electric eels on himself, of battling mosquitos and jaguars left audiences back in Europe spellbound; but he was not just a glorified sightseer. Everywhere he went he made detailed scientific measurements, took copious notes and drew maps, and he was given a hero’s welcome by an admiring President Thomas Jefferson when he finally arrived in the United States, because by now he knew more about Spanish colonial America than anyone else. Back in Europe, he was instantly – still in his thirties – the Grand Old Man of Science, and even more, of Nature, a position he held unchallenged until his death in 1859.

Wulf gives the most vivid account of these years of colossal world celebrity, which intensified steadily as more narratives of South America poured from his pen and Humboldt embarked upon his own whacking great synthesis of all available scientific knowledge, entitled Cosmos, in five fat volumes: think of David Attenborough’s current British reputation, on a global scale. It is a masterly and wholly absorbing piece of biography, shining light on everything from his life trying to be a liberal nobleman at the reactionary Prussian court, to the achievements of his distinguished brother Wilhelm.

What carries less conviction is Wulf’s grand conclusion about what Humboldt and his writings amounted to. The book’s principal title is The Invention of Nature, and she writes, early on: “Humboldt gave us our concept of nature itself.” Perhaps. Her argument is that, in contrast to the Linnean taxonomists who preceded him, obsessed with separating species from each other, Humboldt saw Nature as a whole in which all the parts were connected, as we do today. She also suggests that he anticipated today’s concern for global warming, James Lovelock’s Gaia hypothesis of the Earth as a single organism, and Darwin’s evolutionary theories. Yet while there is no doubt whatsoever that Humboldt was very influential – Darwin read him avidly – to cast him as the fons et origo of the way in which we now look at the natural world feels rather too much like a construct.

It is a certainly a detailed one: Wulf carefully traces the influence of Humboldt on later writers, not only Darwin but also such figures as John Muir and George Perkins Marsh. But it is clear that while many of Humboldt’s observations are as seed-corn for these men, they are scattered about his writing and do not form a cogently articulated single new message such as the others achieved, Muir with his championing of the wilderness, Marsh with his calculating of the cost of the human destruction of Nature, and Darwin with natural selection.

Even so, why has Humboldt been forgotten so completely among English-speakers? Clearly, as Wulf points out, with the two world wars, all things German fell out of favour; but perhaps also there is not quite the substance that she supposes. Darwin’s assessment of Humboldt was “the greatest scientific traveller”, though were Darwin himself known only for The Voyage of the Beagle, he would not be up with Freud and Marx as one of the true shapers of our worldview.

Yet that is not to say that Humboldt does not deserve to be disinterred from his present oblivion. He was a quite remarkable figure, of surpassing historical and human interest, and in this richly documented, brilliantly contextualised and thoroughly engrossing account of his fascinating life, Andrea Wulf has resurrected him triumphantly.

Michael McCarthy was formerly environment editor of The Independent, and is the author of The Moth Snowstorm: Nature and Joy.