A replica of a skull of Homo naledi, a hominin species found in a South African cave in 2013. (Gulshan Khan/AFP/Getty Images)

Rachel Newcomb is an anthropologist and the Diane and Michael Maher Distinguished Professor of Teaching and Learning at Rollins College. She is the author of “Everyday Life in Global Morocco,” due out in October.

A 9-year-old boy stumbles upon a 2 million-year-old hominin clavicle while exploring in a field in South Africa. A paleoanthropologist, kayaking with his family on the Pacific island of Palau, finds a burial chamber full of ancient remains that he suspects might be a previously undocumented race of tiny people. A swashbuckling former diamond hunter discovers a treasure trove of humanlike fossils in a network of caves accessible only to people small enough to slither through an 18-centimeter opening.

In “Almost Human,” the search for hominin fossils reads like an extreme sport. Written by Lee Berger with fellow paleoanthropologist John Hawks, the book documents with riveting intensity Berger’s lifelong fascination with fossil hunting and the contributions he has made to our understanding of human origins.

In contemporary paleoanthropological circles, Berger, who grew up in the United States and is based in South Africa, is considered something of a maverick. He invites National Geographic to document his expeditions for social media, puts out calls on Facebook to invite scientists to join his teams and, rather than hoarding his finds so he alone can analyze them, makes replicas and photos of fossils available for other scientists to study. Traditionally, the journey from fossil discovery to publication has been a slow and laborious one, but Berger is known for speeding everything up. Critical of establishment paleoanthropologists, he views them as “an exclusive club” that refuses to share with others. “I represented a generation that didn’t just want the keys to the club,” Berger writes, “we wanted to open the doors to everyone. We were impatient for a faster pace of discovery and science, and sought collaborations with larger and larger groups of experts outside the traditional schools of thought.”

"Almost Human: The Astonishing Tale of Homo naledi and the Discovery That Changed Our Human Story," by Lee Berger and John Hawks (National Geographic)

Other scientists have sharply criticized Berger for being a relentless self-promoter, too quick to announce to the world that his fossils are rewriting human history. Paleoanthropologist Tim White of the University of California at Berkeley has accused Berger of engaging in “selfie science” and suggested that he is more interested in telling a good story than in sharing scientifically validated facts.

Criticisms of Berger aside, “Almost Human” is a fascinating and dramatically paced book that translates for a lay audience the excitement of paleoanthropology, its debates and its scandals. Berger provides a crash course in the field’s often rocky history, shares his own tales of discovery and offers his version of feuds he has had with other paleoanthropologists. The hominin clavicle, found by Berger’s son, who was only 9 at the time, turned out to be part of several skeletons that were later dated as 2 million years old, representing a previously undiscovered variant of a hominin species that Berger named Australopithecus sediba. Australopiths, first discovered in 1925 in South Africa, lived roughly between 4.2 million and 1.5 million years ago and are believed to be an intermediate species between apes and humans, sharing a bone structure similar to modern humans’ but a brain that was one-third the size of ours. Although Berger asserted that sediba may have been a direct ancestor to modern humans, other anthropologists have disputed this, suggesting that sediba lived contemporaneously with the earliest species of Homo or perhaps was a variant of Homo. Nonetheless, there is little doubt in the paleoanthropological community that sediba was highly significant. Finding skeletons this old yet this complete in itself is astonishing, and Berger has consistently been open about allowing others to study sediba and draw their own conclusions.

Sediba alone would have been a sufficiently exciting discovery for one career, but more was to come. In 2013, Pedro Boshoff, a former student of Berger’s who had gone off to hunt for diamonds and never finished his degree, showed up at Berger’s office looking for work. Knowing that Boshoff was a skilled caver, Berger hired him to explore some promising fossil sites in the area. After several weeks of working with a team of cavers, Boshoff came to Berger’s home late one evening with photos of a mandible and a tiny skull that appeared humanlike but did not resemble anything Berger had seen before. The bones came from a nearly inaccessible chamber in a network of caves known locally as Rising Star, and Berger immediately contacted National Geographic about funding an expedition. He then put out a call on Facebook recruiting paleoanthropologists small enough to slip through the 18-centimeter-wide hole leading into the fossil chamber to come to South Africa. National Geographic covered the entire expedition on social media. After collecting more than 1,300 fossil fragments in 21 days, Berger assembled another team of scholars to collectively analyze them and quickly write papers publicizing their finds.

Here the story grows more controversial. Dating the fossils proved challenging, because they were not found with surrounding geological evidence to help determine their age. What, then, were they? A previously undiscovered form of human, or a type of australopith? Why was it so urgent for Berger to publish his findings so quickly? And how had these ancient hominins ended up in such an out-of-the-way cave? Berger had his theories, but as usual, not everyone would agree with him. To say more would be to give away much of the suspense of this entertaining read. While many in the paleoanthropological community dispute Berger’s theories and methods, there is no doubt that his book’s lively prose will win new fans for paleoanthropology. And in an era when funding for scientific research is constantly under threat, could more advocates in the general public be such a bad thing?

Almost Human
The Astonishing Tale of Homo Naledi and the Discovery That Changed Our Human Story

By Lee Berger and John Hawks

National Geographic. 240 pp. $26