I read the book, Ishmael, by Daniel Quinn, at the suggestion of a colleague of mine who had read it. The quick-and-dirty substance of the book is the angst of a lost child of the 1960s whose desire to change the world was not realized. In a hard-to-believe scenario, he falls under the spell of a telepathic gorilla. To wander further down the path of unbelievability, the monkey has been educated by a wealthy Jew who has purchased him. The Jew dies and his surviving spinster daughter continues to be the monkey’s patron until she dies, at which time he is sold to a circus. The storyline, as dictated by the gorilla, is that through the evolutionary process, from the lightning strike in the primordial ooze to present day, everything was all right until a faction of the Homo sapiens line decided to abandon the wandering tribal life (the “leavers”) to form an agrarian society. This society then proceeds to destroy the whole system in their quest for stability. The endgame of the book is that the unfulfilled, lost, 60s throwback fails again to find fulfillment in saving the world and the bad guys (the “takers” ) win again, only to face the specter of the telepathic monkey’s prophecy that they will self-consume as a society.
In the philosophically-weak rantings of the telepathic gorilla, historical writings are reduced to pantheistic musings that don’t pass historical, scientific, or philosophical muster (it doesn’t really address religion in a believable way). His repeated relating of the migration of the human society from its beginning in the primordial ooze to the despised status of the agrarian-based conquerors doesn’t make it any more true or even believable.
The telepath’s proposal that life was more perfect and idyllic when society was composed of wandering tribes, the so-called "leavers", really chooses to ignore reality. That reality being that tribes were not peaceful, they were predatory; they did enslave each other; there are and have been cannibal tribes in the mix; and there was political intrigue with murders, insurrections, and secret combinations.
The telepathic gorilla repeated over and over in the book the popular but unbelievable mantra that humans evolved from the primordial ooze that had the low voltage electrical charge that started life with a jumpstart that didn’t blow the fuse. This, coupled with all of the scientific laws that would have to be broken to allow this little pet theory to arrive at accomplishment, flies in the face of believability and common sense.
Perhaps the weakest of all of the areas the book faces is the philosophical. My perspective is that the author has no real philosophical strength for his literary work, so he chooses to ignore it. For example as a philosophical point, the whole notion of evolution is left vacant when reason, or self will, either one, is impressed on reality. It turns out that humans have both reason and self will and the battle of ideas could very well come down to self determination versus societal (i.e. governmental) determination—which battle was not addressed at all by this supposed work of “spiritual adventure.”
The book was a tedious, but easy read. I was thoroughly disappointed by the intellectual weakness that was illustrated in this little book and would not recommend it for reading—wait for the movie instead and then skip the movie and watch The Land Before Time 12.
 This should not be confused with DC Comics' Gorilla Grodd, a hyperintelligent, telepathic gorilla featured as a supervillain and the enemy of The Flash (though both are equally believable).
 As far as I can gather, the gist of this "taker/leaver" false dichotomy is this: the "leavers" are organisms that consume only what they need ("I only need five berries today") and leave the rest so that nature can stay in harmonious balance while the "takers" are organisms (i.e. modern human beings) that take as much as they can ("there are twelve berries here, I will eat five and take the other seven in case I need them later" or even "this is a good spot for growing berries, I will plant more so that I can have plenty next year"). Ironically, the very evolutionary theory that Quinn so lovingly promulgates suggests that because there are limited resources (in this case calories), organisms must compete for those resources, in which case organisms that take more are more likely to survive.
 For an alternative to Quinn's fatalism, read my post Responsible Environmentalism.
 "Secret combinations" is an LDS ("Mormon") term that is similar to the modern notion of "secret societies" (see here) except that it is restricted to those secret societies which subvert political and especially divine law for their own benefit (see here).
 I glanced at the Wikipedia article for Ishmael (see here), and I spotted a glaring inconsistency in the book. The telepathic gorilla makes the claim that the "takers" believe they have the right to decide who lives and who dies on this planet. But taken to its logical conclusion, this book is arguing that a lot of human beings who are now living need to die off so we can all go back to being "takers". So the ultimate purpose/goal of the book stands in direct contradiction to the philosophy it is supposedly propounding. And since the book is ultimately "taker" in its nature, how can we believe its message that we should all be "leavers"? Isn’t this really just a sneaky way to convince some of us to die off and "leave" more of the resources Quinn values (species diversity, pristine ecosystems, etc.) for him and his likeminded fellows to "take"?
Angry "Leaver" Gorilla is by Jim Grant, available at http://www.flickr.com/photos/jimgrant/8640443/.