We live in an unresolved mystery. It is the mystery of who we really are. Who are you? Are you a name? Are you a body? Are you a product of your thought process? Is thought a product of your brain? Is consciousness dependent on thought? Do you identify yourself as a "soul"? Try to locate the soul. Is it somewhere inside the body? Is the soul an object? Is the soul another word for the mind? Is the "soul" just one more passing thought in a stream of thoughts? Self-enquiry is the investigation of this mystery. Why investigate? In the absence of certainty, there is fear. Thought and action based on uncertainty and fear inevitably result in confusion and conflict. Human nature revolts at its own ignorance. Nothing is more insulting than the absence or loss of identity. As human beings we possess an innate need to investigate. Self-enquiry is what makes us human.