The push-button ease of e-mail and the never-out-of-touch capabilities of a pager-cellular phone combo have many CEOs wondering how they managed without them. But like most other advances in productivity, they have their dark side. "The potential pitfall with e-mail is overload, and the same goes for pagers," says Gene Griessman, a time-management consultant in Atlanta, and author of Time Tactics of Very Successful People (McGraw-Hill, 800-262-7429, $14.95). "Burnout is a major possibility if you're always accessible. My recommendation: Put yourself in your appointment book. Schedule some time every day for quiet or recreation." Griessman offers four suggestions for keeping e-mail under control:

1. For intracompany e-mail, assign each message a priority ranking--A, B, C or 1, 2, 3--to flag its importance.

2. Preface each long message with a synopsis. The abstracts that precede academic articles are good models.

3. Also at the top of your messages, highlight upcoming action items.

4. Consider establishing a secondary e-mail account for urgent and high-priority messages or key clients.