In the early 80s Gribbin and Cherfas published THE MONKEY PUZZLE- a book that challenged the accepted theory that homo sapiens were descended from apes. The authors argued that we are 100% ape - not a separate species, but a sibling species to chimps and gorillas, more closely related than the horse is to the zebra.

Dismissed at the time as 'armchair theorists', recent research has vindicated Gribbin and Cherfas. THE FIRST CHIMPANZEE is a substantially revised edition of the earlier book, bringing to light these developments.We now know that human beings and apes were descended from a common 'manlike ancestor', and that chimps and gorillas went back to the trees AFTER our ancestors had gone a long way towards becoming human.

The genetic material of human beings, our DNA, differs from the genetic material of chimpanzees, their DNA, by a little over 1 per cent. In the 1990s, this became a scientific cliché, like Albert Einstein’s equation, E=mc², familiar to many people but understood by few. It is usually expressed along the lines of ‘people are only 1 per cent human and 99 per cent ape’. The truth, though is that we are 100 per cent ape – not a separate species in our own right, but a sibling species to the hairy apes, the chimpanzees and the gorilla. People, in fact, are more closely related to chimpanzees (in terms of their DNA) than the horse is to the zebra, the porpoise is to the dolphin, or the sheep is to the goat.

The implications of this discovery attracted widespread attention in 1997, when Simon Easteal and colleagues at the Australian National University in Canberra made headlines by announcing that according to their interpretation of the DNA evidence, using the latest molecular biology techniques, the closeness of the genetic relationship between man and the hairy apes meant that we and they shared a common ancestor as recently as 3.6 to 4 million years ago. This was sensational news, because that date comes after our ancestors had first learned to walk upright (an ‘ape-man’, in common language), and then lost the ability for easy upright walking when they went back to a life in the forests.

Charles Darwin shocked Victorian society by suggesting that man is descended from the ape. This is a shorthand way of expressing the idea that the common ancestor which we share with the hairy apes, the chimpanzee and the gorilla, was more ‘ape like’ than ‘man like’. But at the end of the twentieth century, we have discovered that Darwin was wrong. Apes are descended from man – which is a shorthand way of saying that the common ancestor from which both ourselves and the hairy apes are descended had some distinctly human characteristics, notably upright walking, which the chimp and the gorilla have lost.

Although the story made headlines at the end of the 1990s, all that was really new about it was the sophistication of the techniques used by Easteal and his colleagues to measure, more accurately than ever before, the genetic differences between human beings and their closest relations. As Easteal was the first to acknowledge, the suggestion that ‘apes are descended from man’ was first put forward by us, initially in a pair of articles published in 1981, and then in our book The Monkey Puzzle, published in 1982. At that time we suggested that two extinct ‘man like’ primates from about 4 million years ago, the Australopithecines, were the ancestors of the modern chimpanzee and the gorilla, having abandoned upright walking and gone back to a forest-dwelling life, while our own ancestors (the Homo line) became more efficient walkers and lived in the more open plains. The evidence we had to go on, two decades ago, was less compelling than the evidence Easteal and his colleagues have now gathered, but still compelling enough to make a persuasive argument – an argument which, in the best scientific tradition, has now been tested by the latest experiments and found to be true.

But what does it mean? How could the hairy apes be descended from a man-like ancestor? How can such a tiny difference in genetic material make such a large difference in the physical appearance of human beings and chimps, and bring about such a drastic difference in intelligence that it is we who put chimps into zoos, and not the other way around? Indeed, how can measurements of differences in DNA be used as a ‘clock’ to date the timing of the split between two species? None of those questions was answered by the stories under the headlines about the work of Easteal’s team. But they were exactly the topics addressed in out book. Clearly, the time was ripe to overhaul the material from The Monkey Puzzle in the light of recent developments, and offer it to a new audience. The result is the book you now hold, the most up-to-date account of the most compelling detective story in science, the story of where we came from.