Tell me if this has ever happened to you. You're sitting up half the night, either in a library or in your room, pounding away at a paper or problem set or studying your brains out for an exam. (OK, that much I know has happened to you.) You jump into bed at around three in the morning, priming yourself for your class, review session, or even your exam by telling yourself, "No problem, I'm in bed. Thank goodness I'm getting six hours of sleep." And then it happens: you don't sleep.

You start thinking about your exam, or your class, or about what that guy said about you at lunch, and then five o'clock in the morning rolls around. You start looking at your clock, counting the hours remaining between you and your class or your exam and feeling vaguely ill.

You turn the clock over so that you can't see it; after a while, you begin to fear the light that you know will come streaming in the window far too soon. You lie in bed, alternately staring at the ceiling and the insides of your eyelids, trying to remember what someone once told you when you had trouble sleeping as a child, to pretend that you are lying on a raft on the ocean or that you are floating on a cloud. You start thinking about balancing on a cloud and what clouds are made of and whether one could support your weight, and you don't remember much from physics, but at least you'll be taking Science A next semester, that is, if you pass your Foreign Cultures exam tomorrow, but you need at least a B+ on this exam if you want a decent grade in the class...and then you turn the clock around again and notice that it's 5:30 a.m.. You close your eyes again, and the cycle repeats itself. You have forgotten how to sleep.

But really, there's no problem with not sleeping, you tell yourself. (Insomniacs are always telling themselves things. At five in the morning, there s usually no one else to tell it to.) You're young, right? People stay up all night all the time. It's already 5:30 in the morning, which means that in under two hours it will be seven in the morning, a perfectly respectable time to be up and about. Hey, the dining hall opens at seven-thirty--you could have breakfast! Isn't breakfast the most important meal of the day? Wouldn't that be healthy?

You wander into breakfast, and as you walk, you notice a remarkable spring in your step. You are so light, your body feels so airy that you almost feel as though your legs are reaching to touch the ground instead of pushing to hold you up. You don't even feel tired. As a matter of fact, you feel more energetic than you felt the day before! Not only that, but you feel more alert than ever; when you look around at the buildings outside, everything appears incredibly sharp and focused, and the voices of the people around you sound remarkably loud and distinct. Later in the day during your exam, perhaps you begin examining ordinary objects as if they were quite extraordinary, noticing with tremendous interest the edges of the seat in front of you or the chew-marks on your pencil. But by noon, people are laughing at you at lunch as you contemplate your fork, completely oblivious to anything they've said for the previous 20 minutes. After lunch comes that gap in the day that you have been longing for, those available four hours when you can crawl back into your room and sleep without dreams. The sleep of an insomniac is like the sleep of the dead.

I am one of Harvard's zombies. Every once in a while, I jump into bed late, anxious to fall asleep before I have to wake up six hours later, and every once in a while, I end up simply not falling asleep at all. You might see me in class sometimes, zoned and exhausted. Or on my way to class, talking with a speed and energy remarkable even for a talkative person like me. Some people achieve a similar effect through alcohol or drugs, or incredibly large doses of caffeine. But my erratic situation, and probably that of most of my sleepless friends, is entirely natural.

How does one fall asleep? When I ask people this question, they often say, "By thinking about nothing." I've tried that one. But what does "nothing" look like? How does one think about "nothing" when it consists of nothing to think about--and when there are so many competing things to think about instead? Lately I've had a creeping feeling that I'm not alone.

Harvard fosters insomnia, fuels it and powers it. With a reading period which quickly turns into one very long day in which there is nothing to uo distinguish one twenty-four hour period from the next, not to mention libraries that stay open until one in the morning or that don't bother closing at all (and house libraries that don't even open until one in the afternoon), it's pretty easy to become nocturnal.

But restlessness is much more than that. In the moments between sleeping and waking, between finishing the paper and handing it in, between studying for the test and taking it, between hard work and future failure or success--and maybe even between childhood and adulthood--you can get stuck in time, like a thick mud that grabs hold of your foot as you're stepping with the other foot onto solid ground. You can't think about "nothing" at that moment, because "nothing" is exactly what you fear the most, that somehow you won't make it from Point A to Point B, that you'll sleep through your exam, that you won't get a job or get into graduate school, that you have no idea where you'll be in three years or two years or even six months from now, that you'll be lying awake in bed all night and never fall asleep.

Some of our fears are more rational than others, but ultimately, our successes and failures have very little to do with reasonable expectations and everything to do with how willing we are to take charge of ourselves. And that's damn scary. Would it be less scary if we knew that other, people were up all night thinking about these things too?

Last year during reading period, I was wandering through Cabot Science Library, now the only twenty-four-hour library on campus and a safe haven for insomniacs like me. I spotted a student slumped over in his study carol, emitting a rapidly escalating series of snores, a common sight in an all-night library. Then I saw the slogan printed on the back of his T-shirt: "Sleep Is For The Weak." Next time I'm up all night, I'm going to bring a camera. Dara Horn's column will resume next semester.