Have you ever experienced anxiety? Of course you have. It’s that uneasiness in your stomach as you walk into a job interview or the feeling of nervousness on a first date. And that’s not necessarily a bad thing; numerous studies have shown that moderate anxiety enhances performance. But for millions of Americans, anxiety is persistent and excessive, and significantly interrupts daily life. In fact, the National Institutes of Mental Health reports that 31% of adults in the United States experience an anxiety disorder at some time in their lives.

It might be hard to believe today, but anxiety started out as an extremely positive trait. In fact, you could say you owe your life to it. In the world of our early ancestors, the only people who stayed alive long enough to pass on their genes were the ones who assumed that what was bad was bad, and that what was ambiguous was bad, also. Anxiety told them that even though they couldn’t see the bear right that minute, they had good reason to believe it was lurking nearby. Anxiety put your ancestors back in their cave, postponing hunting for another day. They were safe. Hungry? Maybe. But safe, definitely.

In the 12 fascinating and action-oriented lectures of Treating Anxiety, Dr. Ellen Hendriksen describes the causes and symptoms of numerous anxiety disorders—from generalized anxiety disorder to social anxiety to panic. In her calming manner, and always backed by rigorous scientific studies, she will give you numerous tools and exercises you can employ immediately to help treat your own anxiety. After all, few of us are in danger of being eaten by a bear these days and, as Dr. Henricksen points out, we don’t want to spend our lives hiding in the metaphorical cave.