Heir Apparent is a science fiction/fantasy novel by young adult fiction author Vivian Vande Velde, about a girl who becomes trapped inside a looping virtual reality role-playing game called Heir Apparent.

The same girl appeared as a secondary character in User Unfriendly, Vande Velde's earlier book about a game from the same fictional company, Rasmussem, Inc. She later wrote a third book about this company, Deadly Pink. She does not consider the second or third book sequels, despite their taking place in the same universe as the first one, and she says the three books can be read in any order.^[1]

Vande Velde says, "Heir Apparent was a lot of fun to write because it's about a girl caught in a virtual-reality-type game. Even though Giannine finds herself in a vaguely medieval world, I didn't have to worry about historical accuracy. I also was able to keep throwing all sorts of things at her -- a dragon, an army of ghosts, and a poetry-loving/head-chopping statue."^[2]

The book takes place in Rochester, New York sometime in the twenty-first century future, but the game is set in medieval Europe.

• Giannine Bellisario/Princess Janine de St. Jehan – Fourteen-year-old protagonist whose gift certificate from her dad almost costs her her life. The product of a divorced home, she is being raised by her grandmother. She appears in Vande Velde's earlier book User Unfriendly.
• Andreanna – Queen and wife of the late King. She acts very rudely and bitter toward Janine no matter what Janine does.
• Abas – Cynric's middle son, a dim-witted, strength-obsessed titan who initially jumps at any opportunity to kill Janine.
• Kenric– Cynric's youngest son, who shows a strong interest in magic. Nigel Rasmussem warns Janine not to trust him. She finds him physically attractive.
• Wulfgar– Cynric's eldest son, who was "raised abroad" and has a dark secret.
• Xenos – Craftsman of magical artifacts who likes eating centipedes and spiders, especially chocolate-covered ones. He and Orielle do not get along.
• Uldemar – Blind man who can sense the dead and transform his shape. Janine recruits him to transport her to the home of Xenos's father and then race her to the besieged castle.
• Orielle – Beautiful young woman who specializes in brewing potions. Janine uses her potion of strength against the dragon.
• Sir Deming – Snotty nobleman who tells Janine the news of her royal ancestry.
• Counselor Rawdon – Counselor to the late King. He robs the royal treasury.
• Penrod – Captain of the Guards.
• Grimbold – Ruler of the barbarian tribe north of the kingdom. He is enamored by Queen Andreanna but hostile toward her late husband's kingdom because he claims Cynric stole his crown.
• Xenos's father – Hermit who physically resembles a child and likes riddles.
• Feordina the Knitter – Tiny, sarcastic woman who dresses in plants and directs Janine to Saint Bruce the Warrior Poet.
• Saint Bruce the Warrior Poet – To retrieve the ring, Janine must go before his statue and recite a poem of her creation; if he doesn't like it or it isn't original, he chops her head off.
• Nigel Rasmussem – Sixteen-year-old founder of Rasmussem, Inc. Ironically, his parents don't let him spend too much time on the computer, so he works at the snack counter of his own company's establishment and awkwardly smells like popcorn.
• Sister Mary Ursula – Weird nondenominational nun obsessed with the "Oneness" of the world. According to Nigel, she does not work well with Kenric, and the most common method of winning the game is to give the ring to her.
• King Cynric – The late ruler had an affair with a servant, resulting in Janine's birth, then sent Janine to be raised on a farm because he feared for her life.

• ring – gives a person control over someone else's actions (can be given by a person only once)
• crown – gives a person the Midas Touch—once
• boots – gives a person the ability to walk seven leagues in one step
• strength potion – gives a person super-strength for an hour, followed by extreme weakness for two hours
• hat – allows user to slip into the time stream for five minutes

In her book Constructing Adolescence in Fantastic Realism, Alison Waller discusses Heir Apparent along with several other young-adult novels about virtual reality. She writes that the fact that these novels take place almost entirely within the virtual world suggests "that problems of real life can best be solved within this expressly adolescent space, or that VR environments are inherently more exciting or interesting for teenage readers.... Vande Velde maintains an ironic connection between the fantasy world and a peripheral real world and this minimises the dramatic tension of events within the virtual reality game: we are always aware that Janine's heroic actions and decision-making find reference points in Giannine's real (and in a way rather ordinary) adolescent concerns.... 'Heir Apparent' acts as a space in between the real social relations Giannine faces at home and the virtual adventure she has to tackle as Janine. In a way, she uses the game space to try out new solutions to adolescent problems: to try out a loving father/daughter relationship, for example."^[3]

Heir Apparent won the Anne Spencer Lindbergh Prize.^[4]