As far as i have learned about self-inquiry, it is to discover our self in true sense of realization. Eliminating all the wrong perceptions of oneself, over or under estimations! Clearing your mind with every single thought that may lead to wrong opinion about oneself is the actual essence of self-inquiry. You get to know about the deepest core of your heart.
It is a complete process, an exercise to build better inner to live a better life ultimately, it consists of simple looking question as to
who am i ? where am i going? what do i want? and what is my purpose of being ?
All these perplexed questions are actually hard to find but once you did, you can answer anything in the world !
"Self-inquiry must be done continuously. It doesn't work if you regard it as a part-time activity. "
The greatest of all inquiries indeed. And most powerful as well.