WE COULD wake up one morning and find Widener Library empty.

You read on, perhaps expecting me to reveal a secret passageway out of the stacks or a magical formula that makes hardcovers temporarily invisible.

No, it's much simpler than that. Every book in Widener library is a potential target of theft. You needn't even be that clever or devious to steal books from Harvard; it's as easy as walking out the door.

The book-checkers that guard each exit of Harvard's libraries do not earn their keep. Each week, we flush thousands of dollars down the toilet paying a flock of well-mannered Cantabridgians to arch their necks at students passing by with their backpacks unzipped. It's as easy as pie to steal a book from these folks.

I know. I did it. Six times in one day.

OK, I didn't really commit the AdBoardable offense of stealing books without borrowing them. I simply embarked on a small experiment last week. I checked the books out, concealed them on my person, and walked out with them. Twelve hefty books I heisted: two each from Lamont, Hilles, Widener, Langdell, Cabot and the Fogg Fine Arts libraries. No sweat.

THE checkers never knew what hit them. For one thing, few security guards ever check bags thoroughly. Often they are too engrossed in their reading or conversation to even look up. When they do, it is usually only to take a casual glance at the contents of bags and purses. I usually waltz on by, perhaps exchanging good night's, and I'm off.

Never do they examine all the contents of each bag that passes out the door. (Even the most aggressive of the checkers ignore small pockets in these bags which easily can carry two or three books.) Never do they check oversized coat pockets. Rarely do they examine magazines to make sure they are not library copies.

Most of the time I simply put the books in the small pocket of my backpack. To add a little pizazz, I put them right on top of the main pocket a couple of times. Beginning to think that I was charmed with luck, I even had a friend do it.

No problem.

Don't get me wrong. I am not blaming the book-checkers for their ineptitude. It would be impossible for the most diligent guard to check thoroughly the belongings and person of every student that exits the libraries. When classes let out in Lamont, more than 50 people leave the building in less than five minutes. Thoroughly checking a student would take two or three minutes at least--creating a huge traffic jam.

One could argue that, regardless of their efficiency checking books, the door guards are necessary to restrict entry to Harvard affiliates with proper identification. Theoretically, that's true. But here's the kicker. I entered each of the aforementioned libraries by flashing my Ohio driver's license.

One could also argue that having book checkers--however inept--provides jobs for work-study students. But in my informal survey, five out of six book-checkers were pushing late middle age and were likely not Harvard students. So how about spending that cash on a 24-hour shuttle bus service--or a 24-hour library, for that matter?

AS FOR protecting the books, one feasible solution is to adopt the method used by the U.S. Customs service--random spot checks. A great majority of those leaving the libraries would be allowed to leave unmolested. But a few--let's say one out of twenty--would be stopped and thoroughly checked. The implied threat of being caught should be enough of a discouragement to potential thieves.

Harvard libraries could opt for another possibility that would dramatically increase security: joining the electronic world and installing magnetic detection devices. We could then boast to be on par with the technological giants of the community, like the Boston Public Library, the Kennedy School Library, CVS and Newbury Comics.