Before I came to Harvard, my sister--a member of the class of 1995--tried to give me some pointers on collegiate life. One of her more shocking revelations was that she had, on few occasions, fallen asleep during class.

At the time, this concept was as foreign to me as a Yugo. I had never even considered sleeping during one of my high school classes, and assumed that I would be listening attentively to everything every professor ever said to me.

Boy, was I wrong.

In my three plus years at Harvard, I have majored in sleep. REM. Snoozeville. I have zonked out in so many classes, I can't even remember all of them. Big classes, small classes, sections. Lecture halls with chairs so comfy that it's even better than your own bed, or classrooms with benches so wooden that I wake up with three fewer vertebrae in my back. Good professors, boring professors, weird professors.

Put it this way: I can count the classes I haven't dozed off in on one hand.

Most of my friends think this is bad. They say that if I'm going to fall asleep, why go to class? Or, if you already dragged your butt to class, why not stay conscious?

Incidentally, these are the same people that get all excited when they fall asleep during CS 50, like it's some big deal. They're like a kid that think he's Rambo if he sneaks into the garage and looks at presents before Christmas.

Anyway, my response to their argument goes like so: Sometimes lectures are pointless, but sometimes they're useful--even within a single class. That is, professors have an uncanny ability to fade between the relevant and the irrelevant, so why should I not fade in and out as well?

The keys, of course, are the ability to wake up when lecture gets interesting and to be able to fall asleep whenever the situation permits it. The first skill isn't that difficult to learn--you just have to train yourself to wake up when you hear a change. If the professor drones on, stay on cloud nine; but if he or she stops talking to write on the blackboard, or if you hear notebooks being opened or pens clicking as the poor awake listeners begin to take notes again--now it's time to rouse yourself. Also, this can prevent the embarrassing situation of remaining asleep after everyone has left the classroom.

The second ability is a bit more difficult to get a handle on. You need to have a knowledge of where and when sleep is safe. And that is the focus of the rest of this article.

First, an axiom: You don't want the professor to know that you're asleep. I find this pretty self-evident. To konk out in the first row is a bit rude, and that tenured person is the one that's writing your recommendation.

Therefore, prospective snoozers should always go to the back row to be as safe as possible. But even then, it can sometimes be difficult to know if it's safe or not.

However, it is possible to do a rough estimate given the known factors, which are the lighting, the professor's age, the relative level of the podium to the seats and the number of rows in the auditorium.

First, when I say lighting, I don't just mean how bright it is in the lecture hall; experienced sleepers can doze on the surface of the sun. What I mean is the ratio of the lighting level on the stage/podium as compared to the seating area. It's hard to look from a well-lit place to a dark place; the converse is quite easy. So if the room is dark and a bunch of stage lights are pointing at the professor, it's beddy-bye time.

The professor's age, meanwhile, takes two factors into account: the eyesight and the probability of tenure. Older profs can't see as well as younger ones; moreover, they are more likely to be jaded and tenured and thus less likely to care about a trivial 20-year-old snoozing. Hey, their research grants are still coming in, so it's no skin off their backs.

The reason that higher seats are better is one of physiology. When we look down, our eyes seem to close and our chins drop--incidentally, the same pose as a sleeper. Also, since craning one's neck upwards is uncomfortable, professors usually just look at the first few rows in rooms that have a steep slope (and I don't mean the grading curve). On the other hand, if the professor is on a raised stage, it's obvious who's sleeping and who's not. It's about impossible to sleep with you neck raised upwards, and even if you could your eyes would be obviously closed.

And lastly, the more rows in an auditorium, the better it is for nodding off. Keep in mind that the number of seats is not the same as the number of rows.

The first conclusion from these points is that falling asleep in section or in small classrooms is a bad idea. Not that I haven't done it, but I'm not particularly proud of it. Section is the worst place of all, because the TF is the person that's grading you. Dozing off in a section that's not required is perhaps the lowest on the totem pole one can go. (And yes, I've done that, too.)

Therefore, the only classes one should even consider sleeping in are medium-sized to large rooms, with the final decision being based on the four aforementioned factors. However, in truth, they are hard to compute and more difficult to weigh. Lighting level varies and is practically subjective, while age is difficult (though not impossible) to determine. And how does one know if a given slope of the seating rows is enough?

In practice, you usually rely on personal experience when you're out in the field. As a senior, it is my sacred duty to hand this wisdom off to the youngfolk; so now I shall list every pertinent lecture hall in the order of most to least sleepable in.

Science Center A-D: The Ritz. Not only are there no better halls for this purpose at Harvard now, but I can't even imagine ones that are better. With the Greenhouse Cafe and Chick-Fil-A, the Science Center is one of Cambridge's best bed-and-breakfasts.

The lighting couldn't be better. The seating areas are relatively dark, the chairs are comfy and there are batteries of stage lights shooting at the professors. The rows go back deep and upwards, and the halls are so large it's hard for the professors to pick out individual students.

In fact, I've had my best sleeping experience in Science Center D while taking Physics 15ab. On two separate occasions, I've had involved dreams during class, each involving the professor or the lecture. I'd like to think that on a subconscious level I have vast amounts of physics knowledge, because I sure don't on a conscious level.

Sackler Museum: Almost on the level of the Science Center, but not quite. It's just as dark in the seating area, but the rows aren't sloped as much and the professor is up on a small podium.

Nevertheless, the rows seemingly go on forever, so it takes only a little forethought to be on Cloud Nine during Frank Lloyd Wright.

Also, classes in Sackler are very likely to be Lit. & Arts B's, which are very likely to use slides. And showing slides mean showing slidezzzzzz....

Sanders Theater: I understand that this room was not designed with the sleeper in mind. However, there are opportunities, subtle as they may be.

First off, all sleeping has to take place on the balcony level. The lighting is even and the stage is raised above the ground level, so anything on the first floor is out of the question.

But even up top, the bench seating is so uncomfortable that there are only three options for snoozing: Folding your hands on the first-row banister and resting your head there, slouching down until your knees hit the back of the seat in front of you or simply lying down on a bench.

The first option is out of the question, because everyone in the whole room knows you're asleep--though I have seen people do it. Even John Kenneth Galbraith would get mad at someone passed out on the railing. The second one is possible, but you'll need to bring lower back support (a rolled-up jacket works well). The third possibility is the most comfortable, but the classroom will have to be sufficiently empty, and you might fall into a really deep sleep and accidentally dream of the next lecture.

Emerson 105: Decent. The rows go back very far, but the lighting is bright and the slope is pretty flat. But die-hards like myself aren't fazed by these concerns; if you go to the back row you're pretty safe.

Harvard Hall and Sever: Now we're in the danger zone. These rooms are small, the lighting is very bright and the stages are raised.

Of course, that hasn't stopped me from resting my eyes for extended portions of time on the second floor of Harvard Hall. Maybe that's the reason my GPA is stagnant; maybe it's not.

At least I'm well-rested, though.