You have probably heard the old canard, "Those who do, do. Those who cannot do, teach." Time to set the record straight. Pick a topic that you think you know. Any topic. Now, explain it to 3 different people: a child, a colleague not in your area of expertise, and someone who is completely outside of your social circle--perhaps someone of a very different age than your own. If you cannot explain your topic to them, then you don't know what you are talking about! I know that this may come as a bit of a shock to some--that learning and communicating are flip sides of the same coin when it comes to mastering knowledge. But the classic Greek philosophers had no problem with this. Plato (a student of Socrates, image above) and Aristotle got it. They invented it. Plato and Aristotle formed what would 1600 years later would be called colleges, schools, and universities. The Academy was created by Plato around 387BC. Aristotle, who studied there, formed his own: the Lyceum. Luminaries such as Einstein and Feynman also got it. Look at how they behaved, how they communicated, and what they accomplished. So, what is the lesson here? Stop trying to impress only your colleagues and start communicating what you know to the other 99% of the human race. By doing so, you will dramatically take your own understanding of an area to new heights. You will not only be a Teacher, but an Understander.