Let me begin with a simple, wonderfully freeing premise: You do not need to know everything.

A few short generations ago, it could rightly be said, Information Is Power. That was true when there wasn't enough of it. Today, the motto should read: Information Is Fatigue. We get too much information, and a high percentage of that information is inane, meaningless, enervating. Do I really need to know whom Anne Heche is dating?

Writes Richard Saul Wurman, in Information Anxiety 2 (Que, 2001): "Information was once a sought-after and treasured commodity like a fine wine. Now, it's regarded more like crabgrass, something to be kept at bay."

No, information alone is no longer power. What is power is the right information, a limited amount of information—the information you need, when you need it.

The fact we must focus our learning should be self-evident, but for many years, I struggled to believe it. Growing up, I admired DaVinci, Benjamin Franklin, and other polymaths who excelled in multiple ...