This is part of the reason that, when someone is interrupted, it takes 25 minutes to cycle back to the original task. Once their work becomes buried beneath a screenful of interruptions, office workers appear to literally forget what task they were originally pursuing. We do not like to think we are this flighty: we might expect that if we are, say, busily filling out some forms and are suddenly distracted by a phone call, we would quickly return to finish the job. But we don't. Researchers find that 40 percent of the time, workers wander off in a new direction when an interruption ends, distracted by the technological equivalent of shiny objects. The central danger of interruptions, Czerwinski realized, is not really the interruption at all. It is the havoc they wreak with our short-term memory: What the heck was I just doing?

When Gloria Mark and Mary Czerwinski, working separately, looked at the desks of the people they were studying, they each noticed the same thing: Post-it notes. Workers would scrawl hieroglyphic reminders of the tasks they were supposed to be working on ("Test PB patch DAN's PC -- Waiting for AL," was one that Mark found). Then they would place them directly in their fields of vision, often in a halo around the edge of their computer screens. The Post-it notes were, in essence, a jury-rigged memory device, intended to rescue users from those moments of mental wandering.

For Mark and Czerwinski, these piecemeal efforts at coping pointed to ways that our high-tech tools could be engineered to be less distracting. When Czerwinski walked around the Microsoft campus, she noticed that many people had attached two or three monitors to their computers. They placed their applications on different screens -- the e-mail far off on the right side, a Web browser on the left and their main work project right in the middle -- so that each application was "glanceable." When the ding on their e-mail program went off, they could quickly peek over at their in-boxes to see what had arrived.

The workers swore that this arrangement made them feel calmer. But did more screen area actually help with cognition? To find out, Czerwinski's team conducted another experiment. The researchers took 15 volunteers, sat each one in front of a regular-size 15-inch monitor and had them complete a variety of tasks designed to challenge their powers of concentration -- like a Web search, some cutting and pasting and memorizing a seven-digit phone number. Then the volunteers repeated these same tasks, this time using a computer with a massive 42-inch screen, as big as a plasma TV.

The results? On the bigger screen, people completed the tasks at least 10 percent more quickly -- and some as much as 44 percent more quickly. They were also more likely to remember the seven-digit number, which showed that the multitasking was clearly less taxing on their brains. Some of the volunteers were so enthralled with the huge screen that they begged to take it home. In two decades of research, Czerwinski had never seen a single tweak to a computer system so significantly improve a user's productivity. The clearer your screen, she found, the calmer your mind. So her group began devising tools that maximized screen space by grouping documents and programs together -- making it possible to easily spy them out of the corner of your eye, ensuring that you would never forget them in the fog of your interruptions. Another experiment created a tiny round window that floats on one side of the screen; moving dots represent information you need to monitor, like the size of your in-box or an approaching meeting. It looks precisely like the radar screen in a military cockpit.

In late 2003, the technology writer Danny O'Brien decided he was fed up with not getting enough done at work. So he sat down and made a list of 70 of the most "sickeningly overprolific" people he knew, most of whom were software engineers of one kind or another. O'Brien wrote a questionnaire asking them to explain how, precisely, they managed such awesome output. Over the next few weeks they e-mailed their replies, and one night O'Brien sat down at his dining-room table to look for clues. He was hoping that the self-described geeks all shared some common tricks.

He was correct. But their suggestions were surprisingly low-tech. None of them used complex technology to manage their to-do lists: no Palm Pilots, no day-planner software. Instead, they all preferred to find one extremely simple application and shove their entire lives into it. Some of O'Brien's correspondents said they opened up a single document in a word-processing program and used it as an extra brain, dumping in everything they needed to remember -- addresses, to-do lists, birthdays -- and then just searched through that file when they needed a piece of information. Others used e-mail -- mailing themselves a reminder of every task, reasoning that their in-boxes were the one thing they were certain to look at all day long.