The Prussian naturalist Alexander von Humboldt was once the most famous man in Europe bar Napoleon. And if you judge a man by his friends (as you should), how about Goethe, Schiller, Simon Bolivar, Cuvier, Lamarck, Laplace, Guy-Lussac and Jefferson? And that is only the start of the supper list.

So what happened? Why is he forgotten? For the best of reasons: because he contributed so much to so many fields of intellectual interest that are now separate scientific disciplines. And also because most of his ideas that were once startlingly original are now commonplace. We take it for granted that there are vast rivers running through the seas (but at least the Humboldt Current is named after him). He was the first oceanographer. He was the first ecologist.

The idea that as you climb up a mountain you make your way towards the poles, in terms of plant life, was his (a thought that came to him on his great climb of Chimborazo in the Andes, then by far the highest ascent that any human being had ever achieved). I followed a part of the journey he describes in perhaps his greatest work (Darwin’s inspiration), Personal Narrative of Travels to the Equinoctial Regions of the New Continent, which, like its title, is too long, but I was astonished by its accuracy.

This magnificent biography has it all. But I’m ashamed to say that the story that really stays with me is of his stay in Quito. Humboldt was charismatic, handsome, packed with life. All the girls fell in love with him, including the great beauty Rosa Montúfar, daughter of the provincial governor. She dreamt of his proposal. But on the morning of Humboldt’s departure she discovered that he had run off with her brother.

Andrea Wulf has a firm grasp of the history of science, but not of natural history: there are no apes in South America; anacondas, not boa-constrictors swim past the canoe, and tapirs are not pig-sized. Nevertheless, this is an exceptional biography of an extraordinary man. Wulf deserves our congratulations. It is now time to rediscover the abundant and diverse intellectual pleasures that Alexander von Humboldt can give us.

*Editor’s note: Andrea Wulf writes in response, ‘O’Hanlon seems to be criticizing the greatest scientist of his age when he says that anacondas would be swimming next to Humboldt’s canoe. Yes, anacondas swim these rivers but what was I supposed to do, if Humboldt himself described boa constrictors swimming next to him (and as far as I know boas are capable swimmers)? I do like to rely on my primary sources. There are no apes in South America, agreed, but Humboldt got this wrong (well, his English translator did) when he wrote in his book ‘Views of Nature’ of the “melancholy howling of the small apes” – I should have corrected that in this instance – but specifically I only mention howler and titi monkeys.’ She adds: ‘And when it comes to tapirs being pig–sized I’d say it depends upon the pig …’