What is it that draws people to a book again and again? What makes them itch to get everything else in their lives sorted out so they can return to reading?

There are many answers, of course. Education, entertainment, escape—and that’s just the reasons beginning with E! There’s a particular writer’s style, their way with words. Their humour or their ability to depict hard times and make us feel as if we were living them from the comfort of our chair. However, if I was to make a list, I believe the number one reason readers read is because of character. All the other reasons fold into that one.

Think about your greatest reads. What looms largest in your memory? Is it the depiction of the blasted road leading to Mordor? Or Frodo’s terrible choice as he sways upon the precipice and decides whether to destroy the One Ring? Is it the intricacies of espionage, codes, and dead letter drops you remember in a John le Carré novel? Or is it the moment when Smiley realizes that the traitor is someone he’s loved all his life?

I’d wager it’s the characters. And it is as true for nonfiction as fiction. It is the journey of another human that rivets us to the words: how they overcome their enemies and the obstacles placed before them to achieve their desires. How, so often, their enemies are within themselves, and their obstacles self-erected.

But how are these captivating characters written? What alchemy is it that makes one have such feelings for these people? Note, I don’t say “love.” Some of the greatest characters in fiction are those we hate. Heroes, villains, and ordinary people caught up in extraordinary circumstances are the stuff of great writing. I do use the word alchemy deliberately. Like so much of writing, creating great characters is a process, a series of experiments leading to a specific result. Moreover, it’s the character’s journey of change or evolution, leading to a fully realized human, that engages us.

Every writer will have their own way of doing this. Some write elaborate histories, extensive back stories, detailing someone’s life from cradle to grave—on the page or just in their notes. And while I consider a character’s background and history when I start to get to know them, too much detail for me always feels like I am trying to tell the character what to be. I’d rather they tell me—and I get them to do that by putting them into action. Character-in-action.

A character revealed by what they do, sometimes (but not always) by what they choose to say or not say. I don’t believe in knowing too much before I set out on a story. I want the story to tell me what it will be. I want the characters to do the same. And I get them to do that by writing them doing stuff.

You’ll need to oscillate between the needs of the plot and the needs of the character. Between the dictates of historical fact and the human needs that made that fact a reality. Between knowing something about a person—they were born in poverty in 1620s London—and seeing how they react when presented with an opportunity for riches in the ruins of a country house in 1645.

Create opportunities for your character to show you who they are at the core of the story. I use an acronym in my writing which I return to again and again: COMOCA. COMOCA stands for Character’s Objectives Meeting Obstacles Creates Action.

It is a simplification—and a way to almost trick the mind into the freedom necessary for characters to come alive. If you have too tight a grip on them, if you demand they behave in a certain way on page twenty because you need them to steal the jewels on page seventy-eight your characters may serve your plot, but they will not have a life. They will only be a function of your clever plotting mind.

Now I’m not saying you can’t have both, that a character can’t serve the plot as well as themselves. But think of the character’s objective: what do they want most? Throw an obstacle in their path that prevents them from getting what they want. See how they deal with it. They will have to overcome this obstacle to succeed, and this will force them to learn, change, or grow, which propels the story, ensures your character has agency, and creates tension.

Some might say it’s all the writer’s creativity anyway. But trust me, for characters to really live they must be able to surprise you. The dauntless hero must display some surprising cowardice around snakes (Indiana Jones). The primmest of ladies must get all hot and bothered by the way the local gent looks in a wet shirt (Pride and Prejudice—the Colin Firth version).

One of the most important ways to deepen a character is to get them to reveal their flaws to you. “The Antagonist Within” is a phrase I learned recently, summing up beautifully what I had learned instinctively: that what makes a person interesting is not their virtues but their flaws. Heroes are great to follow into breaches, but would you want to have breakfast with them every day? What if you give your character an objective—like win the girl (or guy)—and the obstacle is their inability to conjugate verbs when in their loved one’s presence? (Reader: I have been there!) Now they have a flaw that must be overcome. They have more depth. You have a clearer idea of the kinds of action that will cause the character to struggle (and to grow)—and that’s someone your reader will want to spend more time with.

A successful playwright once wrote to my father (when he was a young writer) and gave him this advice:

“Let your characters dictate your plot rather than your plot dictate your characters.”

Words to live by (or rather to write by). It doesn’t mean your fiendishly devised plot won’t work. It can but you must let your characters find ways to pursue their goals rather than straight-jacketing them with what you think “must happen next.” Find their antagonist within. Seek ways to reveal them to the reader by character-in-action. If they surprise you, then they will surprise readers, too. And surprise will keep bringing the reader back to the pages until they are all devoured.

Chris Humphreys teaches writing when he’s not writing award-winning and bestselling novels of his own. Chris has authored more than eighteen published books over his two decade career, with such illustrious houses as Doubleday, Knopf, and Orion. Learn more about Chris on his website.