J.k. Rowling Is Famous For Writing Which Books?

J.K. Rowling's "Harry Potter" books have offered countless readers of all ages the opportunity to escape the mundane and immerse themselves in a magical world. But for one little girl, the impact of those stories was much more powerful than magic.

Chrissy Hart read the books to her daughter as the young girl battled cancer, and in a letter to Rowling, the mother wrote "Your words built a castle for her to move into when the prognosis got worse."

LONDON, ENGLAND - SEPTEMBER 27: Author J.K. Rowling attends photocall ahead of her reading from 'The Casual Vacancy' at the Queen Elizabeth Hall on September 27, 2012 in London, England. (Photo by Ben Pruchnie/Getty Images) Getty Images file

Hart's message was recently read by actress Ellie Bamber, as part of a Letters Live performance in London. The charity event celebrates the "power of literary correspondence," and there's no denying the power this letter.

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"I write to you as a mother, a Mummy, of a beautiful little girl," the note to Rowling began. "I'm sure you hear people tell you all the time that your words, your imagination helped them, or their children, in some way. Maybe they were helped out of depression by your works, maybe they drew strength from the knowledge that Neville grew up to be a hero against all odds, maybe you taught a bookish boy that there are friends to be found between the pages of a novel."

But Hart's daughter learned something different from the tales of the wizarding world.

"When I read her your stories, she didn't take to the clear distinction between good and evil, but instead loved the grey characters," the mother recalled. "You taught her that for every chemo she has to go through, there will be the opportunity to fly across a lake on a hippogriff. For every time her heart seizes with fear of pain, there will be me chasing it away with a patronus charm."

Hart said that when things seemed most bleak, "your books turned out to be the fortress we so desperately needed to hide in."

And it wasn't just her daughter who learned lessons in the pages of the "Harry Potter" books.

"You made me [realize] that a mother's courage might come in the form of her tears," she explained, thinking back to the many moms Rowling wrote about. "I might not have the physical ability to block her from what will take her away from me, but I can be loving and gentle like Molly, stoic in my affection like Minerva, protective and loyal like Hermione, and waiting to welcome her home like Lily."

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"Star Wars" actress Daisy Ridley shared a snippet of the moving letter on Instagram.

Sadly, organizers informed BBC News that Hart's daughter died last week.

She wrote the letter to Rowling last month, and in it, she stated, "The most important lesson you have taught us both: cancer may take her away from me in just a few short weeks. I might not be able to spare her the pain. But for every child that is taken too early, people will come together, huddling close in a big group, wands held high to light the dark sky with the love they felt."

On Tuesday, Rowling responded to Hart's moving message with one of her own.