This is an expanded edition of a previously published work. Two chapters have been added to this revised edition. In the summer of 1990, S. Y. Cheng and S.-T. Yau organized a conference in Los Angeles in honor of their professor, S. S. Chern, on the occasion of his seventy-ninth birthday. Published here are personal reminiscences from Chern's large group of friends and students. These lectures reflect the wisdom of this great mathematician and his warmth in interacting with young geometers. The editors hope that through this book, readers might get a glimpse of the life of a great geometer.