Pierre Boulle's novel Planet of the Apes is dramatically different from the films and TV series made from it, but they do share common themes.

Nature versus nurture:

Humans and apes are shown in a reversed hierarchy of our own world, with humans mute, less intelligent, uneducated, and so on. Apes speak, build their own civilizations, write and articulate their own religions and philosophies, practice science and medicine, and believe in their own inherent superiority. Yet when Taylor, the main astronaut character, mates with a "wild" human and has a child, both mother and child begin to learn to speak.

Unpredictability of events, yet belief in fate:

The human astronauts are put through a series of circumstances that strip them of the outer signs of human civilization, clothing, technology, and speech. Eventually, one astronaut is able to escape; yet when he returns to Earth, those who greet him are intelligent, technologically-advanced apes.

Multiple futures or realities are possible: the ending of the novel has two space travelers reading Taylor's account. They regard it as impossible to believe. They are revealed to be apes.

Pierre Boulle's "manifesto" on human nature, Planet of the Apes 
uses as a thematic framework the major weaknesses of the human race, and how they eventually will incapacitate us. 

First, is our lack of balance with technology: Boulle argues that, while humans are have been able to manipulate technology to advance their civilization, it has also allowed technology to dominate them. Rather than keeping on top of our creations, we have rested upon them until we are too comfortable, and the creation gets a hold of us. Think about the invention of the Internet: while it is meant to connect us globally, it has also isolated many who now want to depend entirely on it as a mean of communication thus avoiding social and intellectual real-life contact. 

The second is our tendency to cause havoc. The inability to control our successes renders us into chaotic, anxious beings. The "human neurosis" that is non existent in animals is what sets them apart from us in this fictional futuristic world where a massive role reversal from animal to man has occurred. 

Stemming from these two themes is also the concept of civilizational folly, or the overconfidence on our own capacities. We then start our social constructs; our rules on what is considered "right" or "wrong". Our constant battle to choose who is in charge, and who is in control. All of these things limited the human race in the novel and turned it into a sub-race. 

Therefore, the social commentary of the novel focuses on the follies of the human race as a very intelligent body of knowledge that fails itself more than it should.