There are many books that speak about the journey inwards. One of my favorite writers on this subject is Parker Palmer. One time, I had to buy a book for a friend leaving overseas. Since she is in education, I bought To Know as we are Known. Since it is a relatively thin book and not sealed, I flipped through its content. I was astounded by its content even though I had been rather familiar with Parker Palmer's thoughts. "Holistic knowing is deep self-knowledge that engages the person morally and spiritually with the life around oneself."
Let me end with a poem on loneliness from 李白：