Waking from an unpleasant dream before 5:00 a.m., not by first light finding a crack in the drapes, for it's 15 minutes or so too early for that, the roused sleeper's hand moves on an instinctive tour of the bedside table. This is familiar terrain, even in thick darkness: the easily upsettable plastic bottles of pills—aspirin, Diazepam, B-blockers, C-blockers, melatonin. The experienced hand knows every one, and slides stealthily between them. It weaves its way around the half-empty tumbler of grapefruit juice, and over the face-down paperback copy of The Last Chronicle of Barset until it reaches what it was searching for: the knurled volume knob of the elderly, tinny transistor radio whose broken antenna was long ago replaced with a wire coat-hanger.

It seems to be the hand more than the sleeper himself that is so anxious for news as it switches on the radio and warily retreats back inside the covers. At 4:55, the local NPR station is still tuned to the BBC World Service, and there's a sports roundup on: cricket scores, something about the UEFA Cup; not what the hand was trying to find. When the station goes over at 5 to NPR's Morning Edition and the first news of the day from Washington, D.C., the sleeper jerks into full wakefulness in time for the lead headline.

This is how mornings begin nowadays, with the vague, routine apprehension of atrocity that almost never happens, but happens just frequently enough to justify the hand's habitual excursion across the bedside table. Pacific Standard Time is partly to blame, for the worst things in the world tend to take place while the West Coast is sleeping, or meant to be asleep. Baghdad, Cairo, Rome, Madrid, London, have survived the conventional hours of atrocity by 5:00 a.m. PST; New York is just about to enter them.

Bombs in Baghdad, Scooter Libby, Judge Alito... The hand embarks on its return journey to the radio and the sleeper goes back to the difficult business of sleeping. No atrocity—at least none of the anticipated kind—today, so far. Hours later, diddling away at his computer, he'll click on the BBC website at unreasonably frequent intervals, to make sure that it (and he has a very indistinct notion of what it is) hasn't yet taken place. In daylight, he'll jeer at this behavior as both symptomatic of a neurosis he needs to take in hand and a feckless excuse for goofing-off from work. But he still does it, nonetheless, and dates these unhealthy habits back to September 11, 2001—four years' worth of broken sleep and lost threads in his professional life.

Fear is the smallest ingredient of this compulsion, morbid enthrallment a much bigger one. On the morning, and through much of the afternoon, of July 7, 2005, I was glued to the TV in a house in south London, nearly six miles and a million or so people from the nearest of the explosions. Real shock was an unavailable emotion, so long had an attack on London been a "not if but when" eventuality: The best I could manage was surprise that it had happened on this day and at that hour. There were of course shocking details, but they were familiar, of the kind one glimpses involuntarily when being waved past the scene of a major car crash. Pity for the victims? Yes, but insufficient pity, too overlaid by less worthy feelings—the sense of being sucked into the city-stopping drama of the event, the unfolding whodunit and whydunit, the rating of hurriedly called press-conference performances at the G8 summit up in Gleneagles (Blair good, Bush astonishingly inept), and, overwhelmingly, the certainty that this was not, or not quite, it. With no collapsing towers, no panicked crowds racing through smoke-filled streets, no five-figure estimates of likely casualties, the London bombings, though every bit as devastating to those involved as to the victims and families of September 11, looked, to the heartless eye of the TV viewer, like global terrorism slightly lite.

There's a certain perverse appetite that prompts the waking-before-dawn and the groping hand as it feels its way to the radio in the dark. As we get increasingly caught up in asymmetric warfare, one of whose central definitions is that it blurs the distinction between "military" and "civilian" to the point of nonexistence, we may perhaps be beginning to acquire some of that dangerous thirst for adrenaline that keeps soldiers being soldiers. A friend's brother—an American lieutenant-colonel in the Reserves, just back from a year's stint in Iraq—reports that some of the jolliest moments in the Green Zone occurred when the American embassy came under attack from volleys of rocket-propelled grenades. Office staff and soldiers would be sent sprawling from one side of a corridor to the other, everyone turning white with falling debris from Saddam's palatial baroque stucco ceilings, and frosted with bits of glass from Saddam's shattered chandeliers. Then would come the inevitable remark, spoken in a tone of enormous satisfaction, "That was a big one!"

Big ones—when you survive them—feed the addiction that makes war tolerable, and, more than that, exciting, for the warriors. They keep the necessary flow of adrenaline running through the veins. So, as the disembodied hand snakes past the pill bottles, themselves a piquant memento mori, some truant synapse in the brain anticipates the rush that only the baddest of bad news can bring. It is, one might say, just one more of those post-9/11 things, this insidious and corrupting mental adjustment to the events of the last four years, this disconnect between mind and motor response, this guilty, secret hunger for catastrophe.

This essay is excerpted from Jonathan Raban's new book, My Holy War, which he reads from and talks about at Town Hall Seattle (1119 Eighth Ave, 652-4255) on Wed Nov 16 at 7:30 pm, $5.