A fascinating natural history of an incredibly curious substance.

“Preternaturally hardened whale dung” is not the first image that comes to mind when we think of perfume, otherwise a symbol of glamour and allure. But the key ingredient that makes the sophisticated scent linger on the skin is precisely this bizarre digestive by-product—ambergris. Despite being one of the world’s most expensive substances (its value is nearly that of gold and has at times in history been triple it), ambergris is also one of the world’s least known. But with this unusual and highly alluring book, Christopher Kemp promises to change that by uncovering the unique history of ambergris.

A rare secretion produced only by sperm whales, which have a fondness for squid but an inability to digest their beaks, ambergris is expelled at sea and floats on ocean currents for years, slowly transforming, before it sometimes washes ashore looking like a nondescript waxy pebble. It can appear almost anywhere but is found so rarely, it might as well appear nowhere. Kemp’s journey begins with an encounter on a New Zealand beach with a giant lump of faux ambergris—determined after much excitement to nothing more exotic than lard—that inspires a comprehensive quest to seek out ambergris and its story. He takes us from the wild, rocky New Zealand coastline to Stewart Island, a remote, windswept island in the southern seas, to Boston and Cape Cod, and back again. Along the way, he tracks down the secretive collectors and traders who populate the clandestine modern-day ambergris trade.

Floating Gold is an entertaining and lively history that covers not only these precious gray lumps and those who covet them, but presents a highly informative account of the natural history of whales, squid, ocean ecology, and even a history of the perfume industry. Kemp’s obsessive curiosity is infectious, and eager readers will feel as though they have stumbled upon a precious bounty of this intriguing substance.

The tiny, lungless Thorius salamander from southern Mexico, thinner than a match and smaller than a quarter. The lushly white-coated Saki, an arboreal monkey from the Brazilian rainforests. The olinguito, a native of the Andes, which looks part mongoose, part teddy bear. These fantastic species are all new to science—at least newly named and identified; but they weren’t discovered in the wild, instead, they were unearthed in the drawers and cavernous basements of natural history museums. As Christopher Kemp reveals in The Lost Species, hiding in the cabinets and storage units of natural history museums is a treasure trove of discovery waiting to happen.

With Kemp as our guide, we go spelunking into museum basements, dig through specimen trays, and inspect the drawers and jars of collections, scientific detectives on the hunt for new species. We discover king crabs from 1906, unidentified tarantulas, mislabeled Himalayan landsnails, an unknown rove beetle originally collected by Darwin, and an overlooked squeaker frog, among other curiosities. In each case, these specimens sat quietly for decades—sometimes longer than a century—within the collections of museums, before sharp-eyed scientists understood they were new. Each year, scientists continue to encounter new species in museum collections—a stark reminder that we have named only a fraction of the world’s biodiversity. Sadly, some specimens have waited so long to be named that they are gone from the wild before they were identified, victims of climate change and habitat loss. As Kemp shows, these stories showcase the enduring importance of these very collections.

The Lost Species vividly tells these stories of discovery—from the latest information on each creature to the people who collected them and the scientists who finally realized what they had unearthed—and will inspire many a museumgoer to want to peek behind the closed doors and rummage through the archives.