For more than a century, scientists have raced to unravel the human family tree and have grappled with its complications. Now, with an astonishing new discovery, everything we thought we knew about primate origins could change. Lying inside a high-security vault, deep within the heart of one of the world's leading natural history museums, is the scientific find of a lifetime - a perfectly fossilized early primate, older than the previously most famous primate fossil, Lucy, by forty-four million years. A secret until now, the fossil - "Ida" to the researchers who have painstakingly verified her provenance - is the most complete primate fossil ever found. Forty-seven million years old, Ida rewrites what we've assumed about the earliest primate origins. Her completeness is unparalleled - so much of what we understand about evolution comes from partial fossils and even single bones, but Ida's fossilization offers much more than that, from a haunting "skin shadow" to her stomach contents. And, remarkably, knowledge of her discovery and existence almost never saw the light of day. With exclusive access to the first scientists to study her, the award-winning science writer Colin Tudge tells the history of Ida and her place in the world. A magnificent, cutting-edge scientific detective story followed her discovery, and TheLink offers a wide-ranging investigation into Ida and our earliest origins. At the same time, it opens a stunningly evocative window into our past and changes what we know about primate evolution and, ultimately, our own.