In Bud, Not Buddy, Christopher Paul Curtis tells the story of Bud Caldwell, an orphaned ten-year-old boy growing up in Depression-era Flint, Michigan.

After yet another in a long string of bad foster home experiences, scrappy, resilient Bud strikes out on his own. He sets out across Michigan in search of the man he believes to be his father. Along the way, he encounters a cast of characters and settings that typify life in the Great Depression: he eats with a homeless family in a soup kitchen, kisses a girl for the first time in a Hooverville, and meets a covert labor supporter in Owosso who warns him about the Sundown laws that make it dangerous for either of them to be out after dark. Though his father is never found, Bud eventually finds a home and family with his grandfather, Herman E. Calloway, and his successful jazz band in Grand Rapids.

Written for middle school-aged readers, Curtis uses narrative relatability to facilitate audience connection. The story is told from Bud's first-person perspective, and Bud’s narrative voice is relatable in that it is funny, informal, dynamic, bright, and vulnerable. In large part, Curtis achieves this relatability by making Bud wise beyond his years but still limited to the restrictions and experiences of his age. Bud is clearly driven by logic and observation, but he is still beholden to a child’s conception of the world around him. 

For example, when Bud first meets labor supporter Lefty Lewis, Bud gets into the car and sees a box of human blood. Terrified, Bud interprets this situation in the most logical way he can: if Lefty is carrying around human blood, the man must be a vampire. When Lefty explains the box—it contains donor blood for a pending surgery nearby—Bud uses similarly irreverent logic to reconcile the situation so they can move on: Lefty’s teeth aren’t particularly sharp, he concludes, and, besides, a vampire wouldn’t have such a good sense of humor.

Though Bud himself is slightly younger than the novel’s target audience, this narrative dynamic touches on a theme that is relevant to the book’s readers: the struggle to reconcile one’s youth with one’s ongoing growth and maturity, as well as the constant feeling that adults do not and cannot understand the depths and complexities of youth. “Most folks think you start to be a real adult when you’re fifteen or sixteen years old,” he muses in chapter 1, “but that’s not true, it really starts when you’re around six. It’s at six that grown folks don't think you’re a cute little kid anymore, they talk to you and expect that you understand everything they mean.”

Early on in the narrative, this tension is especially prevalent. Bud is in constant diametric opposition to most of the adults in his life. He spends the bulk of his time and energy trying to outwit and outpace adults for his own survival. Left to create his own semblance of structure in the absence of a trustworthy, reliable adult authority, Bud develops a set of rules to live by: “Bud Caldwell's Rules and Things for Having a Funner Life and Making a Better Liar out of Yourself.”

Interspersed with his ongoing discourse on survival skills and the threat of adults are Bud’s continual reflections on age, maturity, and wisdom. In these reflections, Bud threads together his memories of the past, his ideas of what is missing from the present, and his hopes for the future. In chapter 3, he laments that

It's funny how now that I'm ten years old and just about a man I can see how Momma was so wrong. She was wrong because she probably should've told me the things she thought I was too young to hear, because now that she's gone I'll never know what they were. Even if I was too young back then I could've rememorized them and used them when I did need help, like right now.

As Bud moves through the world, encountering people who challenge and expand his conception of family, adulthood, authority, and maturity, he references his rules less frequently. At the same time, he begins to open up and make more room for connection with adults. The trust and affection he used to reserve only for his childhood librarians eventually extends to Lefty Lewis, to Miss Thomas, the other members of the Dusky Devastators of the Depression, and eventually to Herman E. Caldwell.

The novel's central theme—that even the most independent and solitary person can, with time and care, open up to others—can, perhaps, best be distilled by a memory Bud has of his mother, Angela, in chapter 5. One of her favorite things to tell him, he recalls, was about why his name was “Bud” and never “Buddy.” “A bud,” she insists, “is a flower-to-be. A flower-in-waiting. Waiting for just the right warmth and care to open up. It’s a little fist of love waiting to unfold and be seen by the world. And that’s you.”