The book - The Rabbit Who Wants To Fall Asleep - was written by Swedish psychologist Carl-Johan Forssen Ehrlin and tells the story of Roger the Rabbit, the Sleep Snail and Uncle Yawn on their quest to help the rabbit go to sleep.
One mum wrote on Amazon reviews: "I'm actually speechless. I'm sat here waiting for someone to pinch me. Bedtime just went from taking two-to-three hours to taking 12 minutes. We made it to the middle of page two.”
The book is said to use psychological and positive reinforcement techniques to help children relax, focus and eventually drift off. It has since been translated into seven languages.
Forssen Ehrlin said it is "the verbal equivalent of rocking a baby to sleep".
He told The Telegraph: "I had written books before... but I got the idea for a children’s book while I was driving on a long journey with my mother and she fell asleep. I got the idea of how I could use my methods to help children relax."
The author said he regularly uses the book to get his own son Leon to sleep, and said many parents' reactions have been similar to his.
"I am amazed how successful it has been," he said. "My inbox is full of parents who say it has really helped their children to relax and fall asleep."
One parent who reviewed the book on Amazon said: "Had my boy yawning in about three minutes and fast asleep in 10."
A grandparent wrote: "Read this book to my grandson and when I had finished he turned around and fell into a deep sleep. I read it to my other two grandchildren on a sleepover and they fell asleep halfway through. It's brilliant."
However, it hasn't proven to be a fool-proof bedtime solution. One mum wrote: "We have used the book everyday with our four-year-old old since we bought it and she has on all bar two occasions fallen asleep before the story ends.
"The times she didn't we just started back at the beginning and she was asleep during the first page.
"Of course this is not a miracle cure for bedtime, you still need a calm environment and to tackle the sleep avoidance tactics however, it has certainly made our bedtimes swifter, calmer, less clingy and, dare I say it... she's been consistently sleeping through in her own bed."
Another parent said making sure you read the book properly is important. She added: "Thank you. Worked first time and my daughter actually fell asleep half way through. But I think it's important to read and follow the instructions of this book."
Not all the reviews have been positive.
One mother wrote on 19 August: "My four-year-old child did not like it from the get go.
"She asked me to read something else but I carried on with Roger Rabbit. She then asked me to stop saying her name as she didn't want to be in the story. I left her name out and kept reading.
"She complained further that she didn't like the book. I kept reading. She inched her way down the bed, got up and walked out of the room."
Another wrote: "It didn't work for us, my six-year-old son laid with his eyes closed and I really thought he was asleep, then he woke up at the end, read it a second time and again thought it worked.
"But again woke up and started chatting when I'd finished."
Another negative review stated: "Didn't work for my five-year-old non sleeper. When the book finally finished, she just said "Why do you keep yawning?" (the book tells you to), and "that was boring". It was a waste of £12 to be honest."
One person wrote: "This was a complete and utter waste of money. All it did was creep me and my kids out."
At the time of writing the book had an average of 3.5 out of 5 stars on Amazon. Out of 101 reviews, 51 gave the book five stars, seven four stars, 10 three stars, six two stars and 27 one star.
The author told The Telegraph he hoped to do a follow up book on how to use the toilet. We'd be interested to see how that works.
Are you intrigued? Find out more about the book on Amazon.
If you've used the book, let us know if it worked in the comments below.