Christopher Nolan is driving cross-country with his brother Jonah who tells him about a story he is writing about a person with short-term memory loss. He is going to call the story Mememto Mori which sometimes was written on mediaeval gravestones and means "remember to die". Chris ran with the idea and created a script and made the movie. The following are lines from the script.
Leonard: I have no memory.
Leonard: No. It's different. I have no short-term memory. I know who I am and all about myself, but since my injury I can't make any new memories. Everything fades. If we talk for too long, I'll forget how we started. I don't know if we've ever met before and the next time I see you I won't remember this conversation. So if I seem strange or rude, that's probably……
I've told you this before, haven't I?
Burt: (nods) I don't mean to mess with you. It's just so weird. You don't remember me at all, and we talked a bunch of times. What's the last thing you remember?
Leonard: My wife.
Burt: What's it like?
Leonard: Like waking. Like you always just woke up.