I’m standing on a high lookout near a spectacular three-tiered waterfall in Australia’s Blue Mountains National Park. The peaks in the far distance reflect sunshine scattered through a haze of aromatic eucalyptus oil; the light has turned them a pale and dusty blue. At my feet the land falls away into a virgin forest of graceful, pale-barked trees that runs as far as the eye can see. Farther up the slope are leggy shrubs with flowers resembling bright plastic hair curlers: banksias, I think. When a small bird appears in the foliage below I fix it in my binoculars. White, black and acid yellow, it has eyes like tiny silver coins, and it is wiping its downcurved beak on a branch of a shrub with strappy leaves. I don’t know what the shrub is, and I’m not sure what the bird is, either. I think it’s a honeyeater, but I don’t know what anything is, not precisely. The air smells faintly of old paper and something strangely like jet fuel. I feel lost and very far from home.

I grew up in a house full of natural-history field guides, everything from Locket and Millidge’s 1951 two-volume guide to British spiders, with its hairy, many-eyed line drawings, to illustrated books on trees, fungi, orchids, fishes and snails. These books were the unquestioned authorities of my childhood. I marveled at the names entomologists had given to moths — the figure of 80, the dingy mocha, the dentated pug — and tried to match their descriptions to the drab living specimens I found on the walls of the porch on cool summer mornings. The process of working out what things were often felt like trying to solve a recalcitrant crossword puzzle, particularly when it involved learning technical terms like scopulae and thalli. The more animals and plants I learned, the larger, more complicated and more familiar the world around me became.