Blackburn’s beautiful and empathetic narrative uses memoir, travel, and several sciences to investigate the nature of time by way of an exploration of Doggerland, the submerged landmass that until 6,000 years ago connected Britain to Europe. A phenomenon as well as a casualty of climate change, Doggerland, which at various periods was a savannah and a frozen steppe, existed only vaguely until North Sea trawlers began hauling up bones, fossils, and tools in the early 20^th century. Fascinated with “trying to see through the fact of absence” to what is over yet still exists, Blackburn traveled through Denmark, Holland, and the British coast, talking with archeologists, geologists, and fossil collectors about the deep past. She’s a meticulous observer and her narrative is full of wonderful details, from the laminations that preserve imprints of footsteps or raindrops from tens of thousands of years ago to the rhino fossil with bits of hawthorn in its teeth. Intertwined with these field expeditions are Blackburn’s more personal excavations of time. Revisiting places she once lived, she’s plunged into a past that has all the immediacy of the present; just as when she holds an ancient artefact or repeats an African folktale, she’s struck by the simultaneity of different times. This includes the intimation that “time passes backwards as well as forwards,” and Blackburn’s effort to think her way into the lives of the Doggerlanders as they saw their homeland drowning gives a taste of what people in low-lying areas are beginning to face now as the climate undergoes its next, wrenching upheaval.