There will always be a few of them, floating somewhere near the back of the cloud in my mind that is the things I've done and seen and experienced. But unlike most of the books, films, landscapes, days, meals, trips, etc. that make up that nebula, the unfinished books are not whole and distinct. They aren't discrete little packages I can open up in my memory. Recalling them doesn't give me that thrill of accomplishment, the sense that my life is whole because it is made up of whole elements. Instead, it's like I'm still in the middle of the experience, like the book is still lying open on my bed, waiting for me to come back to it.
I forget about them, but eventually they resurface, always with a little pang of guilt. These are not the books that I put down for a purpose - because they weren't worth my time, usually. These are the books that just got lost in the shuffle, and I can't even remember why I stopped reading them and walked away. Most of the time, it's probably because I had to physically depart from where the book was. I only had a couple hundred pages left in Middlemarch when I had to get on a plane for Uganda, but in that case, I was dedicated enough (or crazy enough) to actually cut the (very large and cumbersome) book apart so that I could carry that last little sliver of it with me to finish. But other books I just left. And I will continue to do so over the course of my life, I'm sure, so that eventually I'll have a whole pile of open books and a whole pile of missed opportunities to add another story to my history.
I'm not a very fast reader, and I imagine there are people for whom this is inconceivable. They could just stay up a few extra hours and finish. This is never a problem for me with watching a film. But I read slowly, and I like to read when I have ample time and energy to really savor the words and the story. I don't dislike long books. In fact, I love the experience of living in a novel for several months, always having it there as a world I can slip back into for respite. But those kinds of books are always in danger of being left unfinished.
Right now, Wilkie Collins' The Woman in White is sitting neglected on my bookshelf. I started it this summer, read it pretty devotedly, but didn't quite finish before the start of the semester. I have about 200 pages left. I haven't touched it for almost three months. But it's still sitting on my shelf, right above my bed, just in case. I will be finishing this book. Just not right now.