I’d been thinking about this semi-permeable membrane that separates nonfiction from fiction for a while, but it was only just recently that this issue directly affected me and my writing. I am a writer of nonfiction, always have been, and proud of it. I write nonfiction not as a stop-gap while I await the Muse to deliver the Great American Novel. I write nonfiction not out of a failure of imagination. I write nonfiction because I find real life compelling, because there is a special force and authority in the real, and, in the most basic sense, because there are just too many good stories out there to think about making any up.

I was researching such a story a few months back. I had immersed myself in the world of Alzheimer’s patients. These were men and women living in a particularly caring, home-like facility, and I wanted to write about the lives they lived. I envisioned a book that would explore the world they, their caregivers and their families inhabited. The more time I spent at this Alzheimer’s facility and the more I got to know the residents, the more I saw this world as vibrant, not depressing -- a world filled with fascinating, quirky people who lived life close to the surface, without inhibitions, without past, without future, without time. It was a world of life and death, friendship, petty jealousies, laughter, love and yes, even sex. It was a quiet world that could erupt suddenly into violence, an odd, off-kilter world that sometimes felt more sane, more right than any other. And so, through the winter and spring I did my research. I spent long hours at the care facility. I interviewed caregivers, administrators, medical experts and family members. I read books. I watched two people die. Then I got ready to write.

This was a compelling story, and as real as it gets. But I struggled with it from the beginning. How could I write about the time the night-shift caregiver walked in on Richard and Margaret having sex in Richard’s room? I could change their names (which I just did); I could ask permission of their families. But I could not really get their consent. They could not remember who I was from day to day let alone that I was writing a book in which they might be characters. It was their privacy I would be invading, and even if they didn’t know it, I did. And what about the compelling family stories I was hearing that families didn’t want me to use? Or the family who did let me into their lives and had great stories to tell, but I wasn’t going to be able to use them because their aging mother died too soon for me to get to know, too soon for me to use as a character in the book? What about the tales the caregivers sometimes told me that, if I retold, could cost them their jobs? Or the terrific story I heard and wanted to use but couldn’t because it actually happened at another care facility not this one? There were so many questions and problems. I couldn’t write my way out of them.

And what about all those “what ifs?” all those intriguing possibilities I kept imagining as the real story unfolded before me: What if Stan, the resident with the fiery temper, had actually punched that caregiver instead of just threatening him? What if Mary’s identical twin sister, who didn’t suffer from Alzheimer’s -- but who was, in fact, too old to travel -- came to visit her? What if Emma, who had been a concert musician but now could not remember how to brush her teeth, sat down one morning at the piano in the common room and started playing? Of course, none of this happened. But what if?

Then, running by the river one morning, the thought came to me: What if I wrote this as fiction? I could use all my research, all the terrific characters and the great stories, and I could do it without hurting anyone and without compromising the people who helped me. I could tweak reality, not a lot, but enough. I could make things happen.

I know this doesn’t sound like much of a revelation as I write it now, but it was to me then. And it was not just an eye-opener in terms of how I might approach this story. It was a necessary reminder about just how porous that membrane really is between genres. And even more important, it was testimony to what I know, what all writers, fiction and non, know and should never let themselves forget: It is the story that counts. Everything else -- assuming we don’t lie to ourselves, to our subjects or to our readers – is up for grabs.

Which doesn’t mean that I’m now happily writing this story as fiction. I still struggle with giving up the authority and power of the real: I am still reluctant to mix and match, still wary of straying too way – or not straying far enough -- from what I saw, from what happened in front of my eyes. But I am considering it. I am poking at the membrane. I am thinking: What if?

LAUREN KESSLER is the author of Clever Girl: Elizabeth Bentley, the Spy Who Ushered in the McCarthy Era (HarperCollins), a Washington Post bestseller, as well as nine other books. She is the editor of Etude and directs the graduate program in literary nonfiction at the University of Oregon. Her website is www.laurenkessler.com.