Assassin hones moral acuity. By moral I mean not a value derived from the Almighty, but an understanding of human nature distilled from experience, what Samuel Johnson defined in his 1756 Dictionary as "such as is known or admitted in the general business of life," what contemporary judges mean when they speak to jurors of moral certainty. The game alerts players to the potentialities of surprise, and especially surprise betrayal, and betrayal is part of the general business of life, even undergraduate life at Harvard. In Assassin, not a stranger but an acquaintance or friend becomes stalker, raptor, assassin, and acquaintance or friend becomes prey, target, probably victim. Maybe the game belongs outside Harvard, but maybe it should endure and prosper here because it teaches that betrayal lurks always within the gates, within any gates.

Evil sneaks inside, steals laptops, burgles rooms, even rapes. Against such intrusion Harvard deploys police, guards, locks, and awareness, what all of us see as a common and largely successful effort against harm. We glance at the stranger, report the lurker, lock the door. About all that Assassin teaches little. No one calls the game Perimeter Defense or Scotland Yard. Yet our continuous awareness, sometimes great, sometimes less, of external threat frequently deflects our attention from the very real harm now and then occasioned by people inside the gates. Assassin is basic training against date-rape.

If it did nothing else, Assassin deserves praise for encouraging undergraduates to think well while always remembering they are involved too in a game demanding some level of awareness. Harvard tends to reward total thinking, the welding of reader with book, the stopping of time in darkroom or laboratory. But only in the rarest of situations is such focus wholly safe. Always a scrap of mindfulness must caress the environment, noting perhaps the softly closing door, the far-off squeak, the scent of perfume or smoke or fear, the look crossing someone's eyes. Full and undivided attention encourages all sorts of surprise, sometimes grisly, and some surprise originates within gates, among colleagues, even among friends about to become strangers.

But far more importantly, Assassin teaches undergraduates how easily the raptor succeeds. Students often remind me of my chickens, twisting heads sideways and down to see with single eyes, always facing the light while scratching, never enjoying the stereo view of hawks and owls and eagles. Like my hens cooped north of my barn, students raised in safe, nurturing environments expect little danger from outside let alone within, and when trouble erupts--the automatic feeder capsizes or a gunfight develops outside Holyoke Center--behavior becomes chaotic. Hens explode from hen house, students run in circles or gawk at shooters (although one dropped into the gutter, remembering a VES 107 digression on curbstone height versus body shape). Raptors find too many easy marks, too many undergraduates who never sense who follow them, who stalk them down to the laundry room; raptors who know how little undergraduates suspect their fellow students, their friends. Above all, the game alerts its players to betrayal by someone known to them. Detecting betrayal, or at least discerning its possibility, makes for painful, wearisome learning, but given what I know of undergraduate life in my 25 years of teaching here, and especially given what I know from alumni in the ruthless, high-powered world beyond Commencement, knowing a bit about betrayal often means avoiding it. Date-rape involves betrayal of trust. So does adultery. So does deliberate sabotage of a project by some team member anxious to advance at the expense of the group--perhaps by seeming to solve something at the last moment. So does embezzlement by a partner. What are the early warning signs of betrayal? I know no patterns, no generic signs. But I know that without alertness, without some moral acuity, no cataloguing of warning signs, no scrap of advice proves useful at all.

Often only a little skepticism, a little suspicion proves enough, but all too frequently blissful innocence rules alone. What Internet user can avoid confronting the harsh possibilities implicit in programs like Finger and Ping? Who uses e-mail without the electronic equivalent of drawbridges, a portcullis, some halberdiers? Lately, the answer seems well-nigh everyone. Too many Harvard students trust, too few know Melville's The Confidence Man, the twisted tale of a masquerader already physically close to his victims, poised to ping.

Assassin offers a different slant of light, the different light that reveals facets of character otherwise hidden, that jolts alertness. Some undergraduates--mostly male I suspect--love the game, and I am glad they do. So long as the Republic requires young men to register for compulsory military service, its universities must necessarily support the skills on which its freedom depends, and a bit of Assassin leads players to remember the primacy of infantry. But undergraduates who enjoy the game grow familiar not just with action and masquerading but with betrayal and protection from betrayal, and in time join the ranks of men--nowadays people I suppose--of good will, what the law still calls the posse comitatus. As I finish a book on this subject now, I find myself marveling at the trust contemporary undergraduates put in vague authority, at the undergraduate willingness to expect authority to be just around the corner when needed. In the absence of authority, when ordinary order goes askew, someone who plays Assassin may be good to have around. A little subtlety, a little of the raptor works wonders when no one has time to call 911, when the cell phone is out of service. More women ought to play now, lest they pay later. More men ought to play, lest they prove useless when push becomes shove, when the night needs repossessing. Assassin sheds only a glimmery moral light, but one that once fascinated Melville and other writers preoccupied with delineating character under stress, with decrying one part of the general business of life Samuel Johnson defined.

John R. Stilgoe is Orchard Professor in the History of Landscape. He plays laser tag in the winter dusk, and he plays to win.