One spring, Annette Lees was given a bat monitor for her birthday—a black and olive plastic gadget with knobs for adjusting volume and frequency and a speaker to announce when a bat was nearby. It is hard to think of a present that you could do less with. Nevertheless, Lees set it to 40 kilohertz and stepped out into the night. Within minutes, the monitor started clacking. “I looked up and saw the quickest flick of something sooty, something fleeting and heart-stopping,” she remembers. In that moment, After Dark was born.

The book is Lees’ highly personal and delightfully discursive celebration of a world that is foreign to most of us, and full of “suspense, lawlessness, hazard, sensuousness and awe”. Chapter by chapter, hour by hour, she traces the goings-on in day’s mirror realm as Earth rolls into its own shadow, plunging land and sea into deepening darkness.

Lees, a conservationist, ecologist, and life-long night walker, is a reliable and informative guide. There are three grades of twilight, we are told early on: civil, nautical, and astronomical. Each begins in turn as the sun sinks lower beneath the horizon, with true night arriving when the sun has sunk so far that none of its light escapes to obscure the faintest stars and galaxies. In After Dark we encounter a great deal of the natural world, of course, from “the first cak cak cak of an echo-locating night-flying Cook’s petrel travelling east into the raised night”, to the synchronised rhythm of glow-worm lighting, and the urban feeding forays of bats in Auckland’s Waitākere Ranges. And here are practical tips: walk a dim forest trail by following the slight gap between leaves in the canopy above (called “crown shyness”), and—this from the 1880s—avoid mosquitoes by eating while wreathed in woodsmoke.

The social history, too, serves up surprises. A woman hunting snails by torchlight is reprimanded for breaking wartime blackout regulations; an appearance of the ghost of Hooker Hut; the eerie seismological silence of Auckland during the national COVID-19 lockdown. With no machinery banging away, no traffic growl, no real activity of any sort, the sprawling metropolis had ceased generating what seismologists call “cultural noise”.

Thanks to its confessional frankness, After Dark is also an absorbing and at times poignant memoir. Whether Lees is being discovered while attempting to creep past a couple on their rural veranda, getting dangerously disoriented in the bush, or reflecting on the death of her young son, she has the rare skill of vividly encapsulating the moment.

Above all, After Dark reminds us of how detached from natural processes we have become, and at what cost. In the early years of street illumination, lamp lighting was linked to the moon’s behaviour—off when the moon was full, on when it was absent. Now, the ubiquitous LED, with its bluish light, “shouts ‘Daytime!’ even in the dead of night”, with disastrous consequences for insects, birds and other wildlife. And with the night sky brightening by two per cent every year, light pollution is increasingly recognised as a global concern. As a corrective, Lees invites us to experience “the company of night animals and insects, the glassy light of stars, the floating moon”. And if you missed the show last night, she says, “Don’t worry, the chance will come again in just a few hours, as it has 4.6 billion times before.”