Seven-Day Magic by Edward Eager, 1962.

John and Susan are brother and sister, living in a perfectly ordinary town in Connecticut. They are tall, good-looking, and good in school and at sports, so they are generally popular and are often chosen for positions like class president. However, their home life is unusual because they are orphans who live with their grandmother, who sometimes requires them to look after her as much as she looks after them. Their grandmother isn’t very strong, but she is spirited and is sometimes tempted to do things that she probably shouldn’t do at her age, like climbing trees. Because John and Susan feel like they have to look after their grandmother, it’s sometimes difficult for them to get out and do some of the things that other children their age are doing, like going to parties. They’re glad when Barnaby and his sisters move to a house nearby because they make life more exciting.

Barnaby and his sisters, Abigail (called Abbie) and Fredericka, become friends with John and Susan. Their father is a singer in advertisements, and their mother is a realtor. Because their parents work a lot to make ends meet, the children are often left to their own devices.  Barnaby is opinionated, stubborn, and sometimes hot-tempered, which causes him to get into fights at school, but John likes him because he’s imaginative and full of interesting ideas.

Barnaby wants to be a writer. He’s secretly writing a story of his own, and he encourages the others to read more. Before meeting Barnaby, John hardly read anything at all, and Susan was mostly into the Sue Barton books, about a young woman who becomes a nurse (a real series that was popular in the mid-20^th century, realistic fiction). Barnaby introduces them to a whole new world of fantasy stories, full of adventure. One day, while visiting the library together, the children talk about the kinds of stories that they like and wish that they could find a really good book full of magic and kids that are like themselves. Their wish comes true in a peculiar way.

On impulse, Susan checks out a rather worn-looking book with a red cover, not really knowing what it’s about but thinking that it just looked kind of interesting. The librarian seems a little uneasy when she takes it and warns her that she can only keep that particular book for seven days, which is surprising because that’s the limit usually imposed on new books, not old ones.

On the way home, the children show each other what they got and read parts of their books aloud to each other. When Susan opens the red book, they are all startled to find out that the book is about them. It starts out just like the real life book and tells about their lives and backgrounds and has their conversation about books they like, word-for-word. The children can tell that this is a magic book, but even while the idea is thrilling, it makes them uneasy. There is nothing written beyond their conversation about books, and the book won’t let them turn pages to see what might come next or how their story will end.

As much as the children like the idea of being the stars of their own magical book, it’s worrying. They don’t know what they’re in store for, and they even worry briefly that maybe their entire lives are fictional, that they might just exist in someone’s imagination, although they don’t really believe that because they can remember their lives before the story began. Barnaby points out that the book specifically mentions that he and his sisters recently moved to the area, but he remembers having lived elsewhere before that.

The children carefully consider everything they had originally wished for in a book: that children, just like themselves, would be walking home from somewhere and a magical adventure would start before they even realized that it was happening and that they would have to figure out the rules of the magic in order to use it for their own purposes. Since the first part of their wish has literally (very literally) come true, they decide that they’re going to have to figure out what the rules of this magic are before they decide what to do next. Since looking ahead in the book seems to be against the rules, they decide that they will have to be very careful about anything they wish for next because their wishes seem to be what writes the story, and they need to discuss it first and come to an agreement about it.

Unfortunately, little Fredericka (the youngest of the children) is too impatient for discussion and immediately wishes for an adventure with wizards, witches, and magic, and she wants it to start right away so that they’ll know that the magic is really working. A minute later, a dragon suddenly appears and scoops up Fredericka, flying away with her!

The others try to figure out where the dragon came from, and it turns out that a stage magician who lives nearby was practicing his act at the time that Fredericka made her wish. When she wished for a magical adventure, the rabbit that the magician was supposed to pull out of his hat turned out to be a dragon. The magician, The Great Oswaldo, is mystified, but he’s destined to play the part of Fredericka’s requested wizard. The children ask him to help them, and he says he’ll try, although he’s not sure how.

As Oswaldo tries various tricks in his magic supplies, they don’t work in the way they usually do. Finally, he is able to make his landlady’s house fly after the dragon, much to the landlady’s horror (she’s cast in the role of the witch in Fredericka’s story). In the magical land where the dragon lives, the peasants inform them that the dragon is always carrying off girls and young women to eat them, and they have to think of something fast before Fredericka becomes his next meal!

This is where the children discover that the contents of the magical book change depending on who reads it. When the magician reads it, it’s full of magic spells. When the landlady, Mrs. Funkhouser, takes it from him, it has household hints. For the dragon, it’s all about dragons. Surprisingly, it’s Mrs. Funkhouser’s household hints that save the day, although it’s Oswaldo who gets most of the credit because one of his pet cats eats the dragon after Mrs. Funkhouser shrinks it.

Oswaldo and Mrs. Funkhouser decide to stay in the magic land (which the children think might actually be Oz, in its early days), where they are hailed as heroes, sending the children home by themselves with the help of Mrs. Funkhouser’s vanishing cream. As expected, this adventure is now written in the magic book when the children have another look at it (although Fredericka argues that the illustrations don’t really do her justice).

Susan, as the borrower of the book, says that she wants their next adventure to be calmer, the kind of everyday magic that just creeps up on you. This is the part of the story where it crosses over with the events in Half Magic (another book in the same series as this one). In these children’s world, Half Magic is a fictional book that they’ve read and liked. Susan’s requested adventure picks up where Half Magic left off, explaining what happened after the other four children (Jane, Mark, Katharine, and Martha) left their magic coin to be discovered by a new owner. Susan and her friends delight in explaining to the young girl who found the coin what it does. The girl says that she had thought that the coin might be magic, but was confused because she didn’t get her wish to go into the future and meet some other children. Because the coin only grants wishes by halves (interpreting that pretty liberally), Susan and her friends (who live in the future), came to meet her instead.

Once again (as is common in this series), it leaves the matter of what is fiction and what is reality open to question. Was it the girl’s wish that brought the other children to her, or their wish that took them into her story? Or Both? Was that fantasy story secretly real, or are Susan and her friends more fictional than they like to think? The author likes posing questions like this, but of course, you never completely know the answers, and in some ways, it hardly matters because the adventure doesn’t require anyone’s understanding for them to take place, which is something that, ironically, it has in common with real life – things frequently happen regardless of whether or not you understand the reasons why. Sometimes, figuring out how things work and to deal with them is about all you can do, never getting the complete “why” behind everything.  That’s pretty much how all the stories in this series go.

After the children explain to the girl what the coin is and how it’s supposed to work, she makes a more careful, doubled wish to go to the future with the other children. Unfortunately, when they get there, she panics when she realizes that she forgot to bring her one-year-old baby brother with her and makes a hurried half-wish for him to be there, too.   Because she didn’t wish right, what she gets is her brother at the age he would be in the other children’s time (about age 37) but still mentally the baby he was back in 1924 (the girl’s time). The “baby” is amazed when he realizes that suddenly he can walk and talk much better than he could before and that he’s suddenly much bigger and stronger than he used to be. He gets hold of the coin and refuses to give it back, telling his little “big” sister that he can do what he wants now, not what she tells him to do. Noting that he can even pick her up and carry her around now, he does that, with the others chasing after him to get the charm and bring him under control. (A somewhat similar incident, where a baby grows up too fast and is dangerously immature, happens in E. Nesbit’s Five Children and It – another instance of Edward Eager playing off her books.)

It’s chaos for awhile because a 37-year-old man who acts like a 1-year-old can’t help but attract attention, especially when he gets it into his head that he wants to drive a train. Eventually, they get the “baby” back under control and to his proper age, allowing his sister to take him back to their own time and plan her future adventures with the coin.

Then, Susan and John’s grandmother gets hold of the book, and it takes her and her grandchildren back in time, to when the grandmother was a young woman working as a prairie schoolteacher. Susan makes a wish for the other children to join them, and they help their grandmother and her students to survive a sudden blizzard. They come to appreciate their grandmother’s youthful personality and formidable spirit even more from the experience. They even get to meet their grandfather, who died before they were born, seeing him rescue their grandmother and her students when he was a young man.

Then, Abbie decides that she wants to try to help her father’s singing career. He typically has to work long hours and never makes very much money, just being part of the chorus on advertisements. She thinks things will be so much better if they can help him to be discovered as a great talent. The others are kind of doubtful about her plan because the book seems to send them on rather “bookish” adventures, related to other stories they’ve read or people’s memories, like in their grandmother’s case because her early life actually did somewhat resemble things from the Little House on the Prairie series (a series which the grandmother enjoys reading for that reason). The other children just don’t know what would happen if Abbie tries to use the book for something more modern and everyday, like their father’s career. She tries it anyway, with some unpredictable results.

During a recording at a television studio (which the children are present to witness), the magic makes their father sing wonderfully but he also does his singing part out of sync with the other singers. He’s sure that he is singing his part at the right time, but for some reason, the other members of the chorus are silent when he sings. The director gets mad at him for singing out of sync and messing up the performance, and the singer who was supposed to be the star gets mad about being upstaged, but the reviewers end up loving the performance. So, while at first it looks like the father is going to be fired, he ends up with more singing parts because of the episode. The only problem is that all the singing parts are silly jingles, like the typical advertising jingles he gets. While he’d welcome more money, he always dreamed of being able to get better parts. However, the magic isn’t quite done, yet. When Abbie meets a playwright who is looking for a new talent to sing in his play, it turns out that he has seen Abbie’s father on tv and likes his voice.

Abbie’s wish is so great and does so much for their family that the kids start thinking that it might be the end of the magic. The seven days are really up, and the book has to go back to the library the next day. However, John and Barnaby haven’t had their chance to wish yet, and each of them wants to have a turn before the book goes back. Barnaby even suggests that perhaps they can keep the book an extra day, turning it in late. Surely a little late fee isn’t too much to ask for an extra day of magic, is it? Abbie is afraid, though, that keeping the book overdue would be breaking the rules and that the magic might go all wrong. She’s right.

Even with the idea of keeping the book for extra time, John and Barnaby argue over which of them will get to go first. The book’s magic, angry about not being returned to the library, turns sour on them, causing them to fight. John angrily tells Barnaby that just because he’s usually the group’s idea man doesn’t mean that he’s the only one who’s allowed to have ideas. (Which, in a way, is something that Barnaby needs to hear because that’s part of the reason why he often gets into fights – he always thinks he knows best.) John and Barnaby fight over the book, and the book gets torn. John ends up with a few pages, and Barnaby gets most of the book, which he uses to make a wish that he refuses to tell to the others. Barnaby disappears, and the others realize that the pages that Barnaby is holding are the last few pages from the end of the book, still blank. Without them, the book can’t end, and Barnaby could end up stuck in the book forever! Can the others find him and get him (and the book) back before it’s too late?

Before the end of the book, John does prove that, although he might not be as quick to come up with ideas as Barnaby is, he does get good ones. After he and the others find Barnaby, John uses his wish to get them back home and to return the book to the library in a most unusual way.  (Actually two unusual ways because he couldn’t quite make up his mind about which was best.  Both of them are homages to incidents in E. Nesbit’s books.)

The book is currently available online through Internet Archive.