Reynolds' book gives a good history of what we know about the ape line up to the 1960s. The book, however, is dated. For example, it puts the break in the human-ape line at 26 million years ago whereas the current understanding based on DNA evidence is 5-7 million years ago, and much of the information in this book is anecdotal (native, explorer stories) or based on apes in captivity (zoos, apes as pets) before much of the extensive field work on apes including by Reynolds himself?) was done.
The book's strength is its account of the early history of human-ape interaction. The obviously close resemblance with humans made the apes especially vulnerable to specimen capture (dead/alive) and to feeding fears about apes as monsters. Interspersed with that narrative are a few comments that stick out. We know of the great ape that once existed in China (Gigantopithecus) and learn that Reynolds likes "to speculate that the elusive 'yeti' may prove to be a remnant population of this giant ape." We also find out that evolution's co-discover, Alfred Wallace, "shot orangs for sport" and that William Hornaday killed forty-three orangs on his trip to Borneo ("in the interests of science") before he became a leader in North American wildlife conservation. Reynolds also notes that as early as 1914, tool use by apes in the wild was known, much earlier than Goodall's widely reported account of tool use by wild chimpanzees in the 1960s. And, in an incidentally interesting observation, Reynolds states that cave art in Spain and France depicts warriors fighting, and this perhaps helps to counter any impression that the intermediate period between ape-humans and post hunter-gatherer humans was peaceful.
In drawing some preliminary parallels between apes and humans, Reynolds says that the value of giving intelligence tests to apes "lies in the opportunity they give of studying the operation of humanoid thought processes at relatively simple levels." In this regard, he writes that "all apes, and monkeys too, do have a complex vocal repertoire of calls, expressions, and postures whereby they communicate their mood, their intentions, or their status to one another. This 'language' extends to man to a great extent, in features such as crying, or glowering, or using a particular tone of voice." For Reynolds, the stress on testing is not about how we are so much more intelligent than apes, but how similar we are to them.
Reynolds is clearly troubled by the exploitive and abusive history we have with apes, and by their bleak prospects for survival. In the last line of his book, Reynolds refers to the human as a "good instinctual ape." While he was making another point, he was nevertheless noting that humans, too, are apes. That summary statement does not square with his observation about the ethics of "exposing these near-human apes" to testing and experimentation. Reynolds writes that "most rational people argue, rightly," that it's o.k. to test for medical breakthroughs that save human lives and lead to a greater understanding of abnormal behavior because "if we accept the principles of evolution by natural selection, we must be logical and preserve our own species before any other." A lot is implied in such a statement. How is it logical to state that natural selection says we have an obligation to our own species, particularly given the historical evidence to the contrary? How is that ("preserve our own species") a logical statement if we are, as his last line suggests, apes?