This is a proper roast of a problematic book.   If you're into that, you'll have a great time! :)

 ***SPOILERS*** 
If I'm being nice about it, this book is a cynical cash-grab riding on the back of the fantasy hype-train that Harry Potter helped to create.  I do not recommend reading this to your kids, as it hasn't aged well.  The author, who is best known for a historical thriller detective series, saw an opportunity and cobbled a series together which he cranked out one after the other. 

What started out as just an okay book with okay ideas quickly devolved into a book that takes a dig at every culture that it encounters.  Leave it to an Entitled White British man to write a whole fantasy series about another culture's mythology and then proceed to be an utter ass about it.   ¯\_ (ツ)_/¯   I looked up this author, and whaddya know, he wrote for two conservative British papers.  The same goes for his wife.  Believe what you want, but there is no place for your jaded-ass world view to bleed into children's literature.  I am so not here for it.  Even if you cut out the problematic stuff, this book still isn't good overall.  It feels like a fantasy written by a technical-minded adult.  It doesn't feel magical.  There's a literal book of djinn rules that's referenced quite a bit, and there's a lot of technical speak about djinn magic.  I don't think his love for fantasy is sincere, and it shows. What he does care about, however, is shitting on every culture he can get his grubby little paws on, sprinkling product placement, making classist remarks, and throwing in a touch of sexism.  Charming, but here we go.   

*At the beginning of the book the children aren't aware that they're djinns. The girl character subconsciously grants the wish of the house maid, who wishes to win the lottery, so that she can visit her daughters in Rome.  She wins 33 million dollars.  The thing is, she says she won't quit her job, which is so unbelievably stupid.  "Her face was stained with tears and her jaw was trembling as she spoke.  "What am I going to do?" she muttered.  "It's such a lot of money.  What am I going to do?"  "Do?" said John, incredulously.  "Do?  I think you'll have a pretty good time spending it.  That's what I'd do."  "I'm not going to leave here, you know," Mrs.  Trump said tearfully.  "Oh, Mrs. Trump, you'll not want to keep working, surely.  Not now that you have all that money.  You owe it to yourself to take things a little easier from now on."  "No, I've been sitting here, thinking about it." sniffed Mrs. Trump.  "I'd miss you all terribly if I gave up this job.  I don't have a lot of friends, you know.  And what would I do?  Go shopping all the time?  That's no way for a person to live.  No, if it's all right with you, Mrs. Gaunt, I'll just take two weeks' vacation.  Go see my daughters.  Give them some of the money, I suppose.  And then come back here.  If that's all right with you."

The author expects us to believe that Mrs. Trump would stay because she loves these rich white folks so much, who apparently didn't pay her enough to even be able to visit her daughters. That she can't bear to part with them, so she will forever be their beloved maid, instead of going to be with her family and living her life servitude-free.  It's such a nauseating concept.

At the end of the book: "Mr. Gaunt was especially delighted to see his children had grown so cultural (IRONIC) and thoughtful, and seemed to have quite overcome his earlier fear of John and Philippa and had forgotten how it was that Mrs. Trump, his housekeeper, came to work every day in a stretch limousine and wore a Tiffany diamond necklace while washing the kitchen floor."  God, this is so disgusting to me.  It's basically like a caricature of how the rich view poor people.  He may as well have said:  "Once a servant, always a servant.  You can dress up a servant in nice things, but they'll still act like a servant and think like a servant!  What would poor people do all day if they didn't have the purpose of working for the rich?"  Screw you, P.B. Kerr.  Screw. You.

*At one point they travel to Cairo.  The kids are eating a spicy dish and tell the butler he should try some.  This character says he usually doesn't eat food in the country because it's dirty and that he eats baby food instead.  How is this relevant to the plot, you may ask?  It's not.  The author is just a hateful dickhead.  "I must admit it does smell rather good," said Mr. Groanin.  "Ordinarily I avoid the food in this beastly country.  The standards of hygiene are not very good.  It's only too easy to get what they call, with considerable understatement, Gyppy tummy."  Mr.  Groanin laughed bitterly.  "Let me tell you, Gyppy doesn't begin to cover it.  Borgia tummy more like, Crippen tummy, or some other notorious poisoner.  Or maybe William Wallace tummy after that Scots rebel who was famously disemboweled by Edward Longshanks.  But not Gyppy.  Gyppy is much too cozy a word to describe the full gripping, gut-gnawing horror of an upset stomach in this godforsaken place."  John wolfed down a large forkful of Creemy's Special with noisy relish.  "But how do you stay alive if you don't eat anything?" he asked.  "I have a fridge in my room," said Mr. Groanin.  "It's full of bottled mineral water and jars of baby food that I've brought from London.  I eat that."  "You eat baby food?" said John, almost choking with astonishment.  "Stewed apples and pears, creamed rice and apricots, and that kind of thing?" "It's all sterilized, you see," said Mr. Groanin.  "In little sealed jars.  In this filthy country, it's the only food I've found to be one hundred percent reliable in the tummy department." 

Then a couple paragraphs after all that he smells the food:  "Not a bad cook, that Creemy, I'll give him that," he said grudgingly.  "If you like foreign muck."

*Critical comments about the French and a remark implying them as unclean.  "Did you notice her eyes?" said Philippa.  "It was weird.  When she looked at you, it was like you weren't there."  John shrugged.  "She's French.  They all look at Americans like you're not there."  "Not just Americans," said Nimrod.  "They think that way about pretty much anyone who's not French, really.  Yes, it's what they call civilization."

And another scene: "She may be French but contrary to popular belief, even the French wash their hair now and again."

*They arrive in Moscow and have to come up with a distraction at an airport because an evil djinn is trapped in a jar and an official wants them to open it, but they can't, or he'll escape.  So, she conjures roaches onto his hat.  "That was quick thinking, Phil," said John.  "Well done.  The roaches were inspired.  Wherever did you get the idea?"  "Roaches?" Philippa pointed at the counter of a nearby coffee bar where several cockroaches were making their way lazily across a piece of uneaten cake.  "The place is crawling with them.  I didn't think a few more would look out of place on that guy's hat."  There are thousands of distractions that the author could have thought up.  The possibilities are endless.  But he chose a distraction that would give you the first impression of Russia being a dirty, cockroach-infested place.  Their tour guides are portrayed in a bad light, as well.  The main characters decide they don't want to go further on their expedition north and the male tour guide (who is described as gap-toothed, having dirty spectacles, and a straggling mustache) says he won't refund them.  There's also a woman tour guide who belches loudly every time she loses at a game of cards and is described as having teeth almost as bad as the man's. 

In another scene:  "The only reason you're not dead already is because I haven't decided if I'm going to eat you or throw you into the world's deepest cesspit, which, in case you wondered, is in a hotel in St. Petersburg, Russia.  Believe me, you have not tasted real suffering until you have stayed in a Russian hotel.

*There's a scene where they have to rob the British museum to get an artifact prevalent to the plot and the children wear BLACK FACE.  Not a mask or a sock over their head like any sane person would do.  Literal black face.  "When the twins were dressed in a way they considered as suitable for carrying out a burglary (with roll-neck sweaters, blackened faces, and haversacks)"

In another scene:  "I feel like a criminal," said Philippa.  "I daresay that's because you insisted on looking like one," remarked Nimrod, pouring himself some more tea.  "Blackened faces, roll-neck sweaters, leather gloves, sneakers?  If I were to dress like that I would call the police and have myself arrested immediately.  The two of you appear positively desperate."

And another:  "He was just on the verge of running out of the room to raise the alarm when the smoke cleared with unusual rapidity to reveal two children, about twelve years old and both dressed in black with boot-blackened faces, like two small burglars."

As a minimal sidenote, there are also a couple scenes where it is established that the girl character LOVES pink.  This isn't as big of a deal compared to some of the other stuff, but there really wasn't a need for it, either.  But the poor guy couldn't help himself!  I mean, she is a girl after all.  Every girl ever to have existed is obsessed with pink, right?  My eyes can't roll any harder.  By comparison, the boy picks out sophisticated blacks and grays.  UGH.  Spare me.   

Lastly, there are multiple scenes in which Coca Cola is mentioned.  Enough times that I just know in my bones that this author had a Coke-exec friend who told him he'd get a big fat check if he advertised Coke to children in his children's book.  In almost every scene where the children eat, Coca Cola or Coke (both names) is mentioned as their beverage of choice.  In a scene where they need to travel inside a container as djinn, they go in a Coke bottle.  It felt too blatant to be a coincidence. The word soda could have easily taken the place of a brand name.

I can understand why someone who grew up with this book might love the idea and the adventure, but as someone who had no attachment to it, it was hard to overlook the bigoted views that the author couldn't help but put into his book.  I won't be reading the other books, obviously, but I am honestly curious if the xenophobic trend and blatant product placement continues in the series.  If it does, that's pretty toxic and harmful.  Maybe some of this stuff won't seem like a big deal to people, or they think kids won't notice.  The thing is, younger people, whose brains are still developing, lack the critical eye of an adult.  A child will take things at face-value, especially when their guard is down.  If they're reading something with rampant xenophobic remarks under the guise of a fantasy novel, on some level that does have an effect on how you might perceive other places.  A kid may innocently repeat a comment in this book, thinking that it's true, and that wouldn't be their fault.  It's the fault of the author. 

TLDR, this author knew what he was doing.  There's no doubt in my mind.  I think the world is a hard enough place as it is without a hateful person ruining fantasy for children. In all seriousness, *** I WOULD RATHER READ TWILIGHT,*** which is something you would never hear me say under normal circumstances.  Thanks for coming to my Ted Talk.