A resurgance in dream research is exploring how dreams are a tool for self-discovery.

Michele Spatari / AFP via Getty Images hide caption

Michele Spatari / AFP via Getty Images

We spend about two hours every night making home movies in our minds. Over a lifetime, that adds up to about seven years of dreaming.

For most of human history, those movies were considered sacred. Many early civilizations believed dreams were messages from the gods. In ancient Greece, people slept in temples hoping a dream would bring guidance or healing.

By the 1970s, scientists took a far less romantic view. A few psychiatrists likened dreams to the brain's attempt to make sense of random signals , and their theory threw cold water on the idea that dreams were meaningful.

Psychologist Rosalind Cartwright, known to colleagues as the "Queen of Dreams," pushed back. She believed dreamwork could be a form of therapy and made her case in books including Crisis Dreaming, co-written with Lynne Lamberg and The Twenty-Four Hour Mind .…