Movies that are largely about illness can be harrowing experiences. “Wonder” moves the genre to a better region. Based on R.J. Palacio’s 2012 children’s novel, it uses the drama for a study of the grueling, resourceful work good people can do to help a single challenged life. But it’s never a mawkish ordeal. Viewing it is a surprisingly enjoyable experience rather than a serving of inspirational broccoli.

A large part of its focus is Auggie Pullman (Jacob Tremblay), a bright, alert boy who digs “Star Wars” and X-Box gaming. Like a lot of 10-year-olds, he’s is anxious about entering fifth grade, which he’ll do at the middle school in a private children’s academy. He was born with deformity of his eyes, ears and facial tissues, a condition he has kept hidden when he’s in public by wearing a toy astronaut’s helmet.

He’s been home-schooled up to this point by his protective mother, Isabel (Julia Roberts). She’s as anxious as he is while his father, Nate (Owen Wilson), and teenage sister, Via (Izabela Vidovic), prepare him for his stressful but important transition to shared classrooms.

Director Stephen Chbosky has experience making this sort of film. His directorial breakthrough was an adaptation of his own novel, 2012’s “The Perks of Being a Wallflower.” This film at times has the visual blandness of a tele-movie, but Chbosky handles his cast impeccably.

Tremblay, an excellent young talent in “Room” and “The Book of Henry,” appears in disfiguring prosthetic makeup that never diminishes his sensitive and delicate character work. When a bullying boy at school likens Auggie to Gollum, it’s a senselessly cruel comment. But on another level, it’s an accurate compliment — combining the look of youth with old age, Tremblay is a remarkable performer.

While Auggie’s looks take considerable getting used to from his classmates (especially Bryce Cheisar’s extra-villainous Julian), he could hardly have a better staff. As the school’s principal, Mandy Patinkin offers a master class in treating difficult children like respected adults and their parents vice versa. His homeroom teacher (Daveed Diggs, irresistibly charming in the Netflix series “Unbreakable Kimmy Schmidt”) is the sort of flawless mentor that can make kids think of education as a dream career.

Auggie’s difficulties are partly pushed at him by immature classmates and partly self-inflicted. The film takes the time to consider its inhabitants in depth, explaining that kids who mock empathy and inclusiveness didn’t develop those personalities on their own.

The story moves across four episodes, each framed like a chapter that carries the name and perspective of a different character. Everyone sees the story with a point of view that enriches what has come before, following parallel developments that range from first romance to gradually developing an ethical sense of the world. The players aren’t equally balanced.

Two of them drop from their intervals surprisingly fast, but that’s a quibble. Most of “Wonder’s” novel turns, like the plot twist that arrives as two characters across town connect through their computers in a game of “Minecraft,” are finely crafted.

The biggest surprises may be the deft work by the marquee stars. Roberts is highly moving as the combative mother, a saintly shrew. You can’t take your eyes off her.

Wilson needs to be seen here, too. He has done lots of work that’s all baloney and bombast, but not here, not for a moment. He pushes beyond every shred of dishonest actorish self-consciousness to create a truly uplifting performance. Without unwarranted heartstring-yanking, he’s saddened to tears and tickled to laughs. You probably will be, too. I was.