The book is written as if Henderson is the author because of the first-person narrative. He first gives out deeply personal details about himself (hes 64, weighs 230 pounds, a huge nose and mustache) and that he went on a trip to Africa to find some relief from his boredom with being happily married to a wife who never complains, a personal net worth of $3 million (worth approx. $26 million today) courtesy of his famous scholar father and having had lots of children. His trip to Africa proceeds to give him even more to ponder about the nature and complexity of human behavior and cultures.
Arriving at Africa, he is greeted by a poverty and famine-stricken village that celebrates his physical victory over a semi-friendly battle with their king Itelo but after he accidentally destroys their water cistern, he leaves out of guilt (there's a good chance he was going to get kicked out anyways). He is then greeted by a slightly more resources-rich village that rejoices over his supposed extraordinary strength and choose to make him the Rain King, which he realizes he does not want to become.
Saul Bellow states this is his favorite book that he's written. When the book was first published it received divided reviews from critics but today is acclaimed.
- A.I. Is a Crapshoot: Henderson when he arrives at the Arnewi village thinks that because he knows more about technology than the Arnewi people, only he can fix their problem with the frogs contaminating their water. He constructs a bomb using gunpowder from his .375 H and H Magnum, a flashlight case and two batteries. The result is disastrous ending in many cattle dying and the cistern destroyed.
- Animal Motifs: Henderson compares himself to a pig, then a domestic cat, and then a lion. The Wariri people state that everyone has a personality comparable to an animal's.
- Author Avatar: Saul Bellow claims that Henderson is more similar to him than any other character he's written.
- Baleful Polymorph: Whoever is Rain King shall be transformed into a lion.
- Big Beautiful Woman: The Arnewi people consider big women to be more attractive.
- Blatant Lies: Henderson's daughter Ricey after being accused of stealing a baby claims that it's her baby, though Henderson can tell that she only had breasts since last year. It also doesn't help that the baby is completely black while Ricey is a white woman.
- Breaking the Fourth Wall: Henderson often refers to the audience as "you" and openly treats this book as a public diary for anyone and everyone to read.
- Chick Magnet: Henderson becomes this the instant he moves the giant wooden statue of Mummah which the Wariri village's former weightlifting champion, Turombo, couldn't do. But then Henderson deduces Turombo feigned inability to lift Mummah just to avoid being forced to become the king and transform into a lion.
- "Could Have Avoided This!" Plot: The book often implies that Henderson could have avoided his Rich Boredom and the voice screaming "I want I want I want" in his heart by having become a doctor in spite of already inheriting wealth from his father. Henderson has been mostly dormant and inactive most of his life because he didn't have to work to get rich.
- Covers Always Lie: Subverted, although this has nothing to do with the book's cover. It's about the people who Henderson meet in Africa believing you can tell a person's personality and character just by looking at them.
- Dystopia: The Arnewi village has been devastated by the frogs who invade the water and render it non-potable. It's so bad that the newborns cannot get any milk from either the cows or their own mothers, to the point that the newborns display anger over this.
- Journey to Find Oneself: Henderson claims this is why he traveled to Africa.
- Meaningful Name: Lily's first husband was Hazard, who gave her a good punch in the eye.
- Nice Job Breaking It, Hero!: Although done out of good intention, Henderson in his strategy to destroy the frogs ends up destroying the Arnewi people's cistern instead, depleting their entire water supply and not one frog dies.
- Oh, Crap!: Henderson realizes that King Dahfu only wants him around to be the successor as Rain King because it turns out whoever is King will ultimately transform into a lion and Dahfu wants to transfer that curse to him.
- Rich Boredom: Henderson is bored out of his mind by how much wealth he has, which was passed down to him by his father, a famous scholar who wrote a book about the Albiensians. In fact, Henderson never even had to work for a living to become rich. His net worth comes out to $3,000,000 after taxes so under U.S. tax code his father must have made $5,000,000.
- Rich Idiot With No Day Job: Henderson. No day job? Check. Rich? Check. An idiot? Well, he did blow up the Arnewi people's cistern which is something you can't do without putting in an awful lot of effort into. So again, check.
- Screw This, I'm Outta Here!: Henderson finds his homeland, the United States, unable to continue giving him anymore excitement into his life which is what causes him to travel to Africa and stays there for most of the novel. But then his unpleasant stay in Africa and having to avoid turning into a lion makes him invoke this trope again to return back to the United States to start his life over again instead of staying as the Rain King.
- Victory Is Boring: Henderson has difficulty finding any real challenges in life no matter what he does.