Now that I have written two nonfiction nature-travel books and one science-fiction political-comedy, I have to say that writing fiction is more fun than nonfiction, but also more frightening.

With “Cool Creatures, Hot Planet: Exploring the Seven Continents” and “Endangered Edens,” I was pretty much limited to telling stories of adventures that I had already lived through, making them as funny as possible, and adding some biting political commentary.

With my new novel, “Time Is Irreverent,” I had to make everything up. Sure President Handley is obviously based on Donald Trump, and I have either visited or lived in most of the places Marty Mann and Nellie Dixon passed through on their epic road trip across global warming-ravaged America in 2056, but other than that, the adventure came from deep inside my brain.

Actually, just as every religion ever invented has members who claim to have had a personal experience with their god, I had the same personal experience with my characters. When Nellie Dixon entered the story, both she and Marty Mann took over the typing. I sat back and let them dictate to my fingers what to type next. In fact, I vividly remember typing late one night and then reluctantly going to bed while Nellie was in peril. I honestly didn’t know how—or even if—she would survive. I barely slept and was up early the next morning to find out her fate.

Sure, deep down I knew my characters were creations of my imagination, and that all the outrageous things that Marty and Nellie did were really a part of me, but I tried not to think in terms of reality for fear of losing the magic that was happening.

I wrote what for me would have been the ultimate novel to read if I were buying it for my own entertainment. So far, the reviews have been good, and people are liking my creation. Nevertheless, I know that some will read the book and not even chuckle at what I think is hilarious, and others will be upset with the book’s politics.

When those first bad reviews come in, they’ll be hard to take because my first instinct will be to interpret them as a rejection of a tour of my brain. I will need to rely heavily on a sentence I’ve said to myself many times over the years: “Not everyone likes the Rolling Stones.” In other words, no matter what a person does, in any art form, there will always be someone who doesn’t like it.