During her run as The Bachelorette, it certainly seemed as if Hannah Brown was an open book.

But go ahead and actually open the new book that Brown has written?

And you'll learn a whole lot about the Alabama native.

In this memoir ("God Bless This Mess"), for example, the 27-year old delves into how she suffered persistent stomachaches in fifth grade.

To determine the issue, Brown went in for an MRI ... which led to the discovery of “a tumor the size of an egg” on her pancreas.

“They sent me for a biopsy, and a day or so later, my dad got a call with the results -- not from our regular doctor, but from an oncologist. The tumor was malignant.

"Cancer. Pancreatic cancer -- one of the deadliest forms of cancer there is,” Brown writes, dropping quite the bombshell.

Hannah learned, thankfully, that the cancer had not spread anywhere else on her body.

“On the day of my surgery, I wasn’t scared about what was going to happen to me. At all,” she recalls.

“Even though my mother was in tears and my dad looked as worried as I’d ever seen him in my life as the nurses came to wheel me into the operating room, I looked up at my mom from my hospital bed and said:

"‘Mama, I’m going to be okay.'”

The operation ultimately did not leave behind any cancerous cells.

“I had to go to checkups a few times a year or so after that,” the Dancing With the Stars Season 28 winner notes.

"But nothing else ever turned up in my scans or in my bloodwork."

Wow. Amazing. We've never heard of an 11-year old with pancreatic cancer before.

Elsewhere in this same book, Brown tells yet another shocking story.

She was six years old. She was getting ready to perform at a recital. And her dad pulled her away to tell her that her aunt and very young cousins had been murdered.

"When my mom told us that somebody had come into their house and ‘hurt them,' it terrified me in the deepest parts of my heart," Hannah writes.

"I didn't know the whole story with all the details until years later, but coming that close to something so awful, so terrifying -- it was a turning point for me."

The author added:

"It changed everything. I was no longer living in the innocence of an untouched childhood."

E! News has actually shared a full excerpt from Brown's book -- in which she explains how her mother told her that Aunt LeeLee, and Robin and Trent were "now your angels in heaven."

How has she persevered through such a tragedy?

She writes:

"The only way to make it through all of this at such a young age was to believe in something so much bigger than me.

"Without my faith in God, and in heaven, I'm not sure I would ever have slept through the night again. I still have trouble sleeping now...

"I wouldn't begin to heal until I was in my mid-twenties, in the presence of a therapist. And until I opened up about it in this book, almost no one knew about it.

"So now, I'm just hoping that you, and anybody else who hears about it, will take this story and treat me gently with it."

Brown, of course, chose Jed Wyatt as her Bachelorette winner, only to eventually split from him.

On a far lighter note, she also writes in the memoir about intercourse with him versus intercourse with another suitor, Peter Weber.

"I’ll be honest here," confesses Brown in the book, which is now on sale.

"The sex wasn’t as good as it was with Peter."