David Allen is author of the best-selling Getting Things Done: The Art of Stress-Free Productivity and one of the nation's leading gurus of personal time management. His time-management system emphasizes acting on incoming information right away -- either by completing the action, if it can be done in a few minutes, delegating it, or filing it away in specific to-do and follow-up folders for a time set aside for larger tasks. (Indeed, Allen has a few disciples here at Technology Review.)

When we caught up with Allen this week, we asked him what he thinks of the latest technological tools for tracking tasks and commitments, such as Google Calendar, which was launched last week (see "Google's Time Keeper").

Technology Review: Computers and the Internet let us do more things, but can they really help us get more things done? How does technology fit into a good time-management system?

David Allen: First of all, you don't manage time. Time is time, and it can't be managed. What you manage are commitments. The calendar will let you manage, at a maximum, three or four percent of what you have to do. What you really need is a way to keep track of your commitments. Then you start to get a sense of the huge volume of commitments you've made, and you are able to review those commitments.

The vast majority of gadgets do nothing more than speed up how you slice and dice this information. There is no difference between having your calendar in your pocket or having it on the Internet. I have a Palm, and I wouldn't even use that unless it had a month-at-a-glance feature, which is the only reason that Palm is a little better than a lot of the other gadgets for handling digital information. But it has an equal downside: Out of sight, out of mind.

Often, you need to look at the list of calls you have to make when you're at your phone and when you have some time. If a computer makes that information more ubiquitous and easier to access, then, to that degree, it helps.

But a computer can also give you the illusion that you are organized -- when all you are really doing is keeping track of placeholders. In the geek world, a lot of people love my stuff, because it supercharges what you can get done. But if you are overworked, you are going to be just as tired if you're using an electronic or online calendar as if you're using a paper one.