Hao Wang (1921-1995) was a prolific researcher and writer in mathematical logic, computer science, and philosophy. He is known for the close relation he developed with Kurt Gödel during the last decade of the latter's life and the two books about Gödel that he published after Gödel's death. This volume of essays covers to some extent each of these fields of Wang's activity but with greatest emphasis on philosophy. Wang spent the first twenty-five years of his life in China and continued to identify himself as Chinese, and in later years he returned to China several times. The volume adds to the picture of the Chinese side of Wang and his engagement with the intellectual life of his own country during a turbulent period. Wang's writings in Chinese are surveyed, and two translations are included of short essays on two Chinese scholars, his teacher Jin Yuelin and his friend from student days He Zhaowu, as well as a short memoir of Wang by He, written shortly after Wang's death. Another writing of Wang published for the first time is an edition with introduction of an exposition by Wang of Gödel's views on sets and concepts. Essays on Wang and his work include a memoir of collaboration with him on Gödel's philosophy by Eckehart Köhler, an account of two classic contributions to computer science and logic by Martin Davis, and essays by Abner Shimony on his distinctive view of the nature and method of philosophy and by Juliet Floyd on his reflections on the philosophy of Wittgenstein, who fascinated Wang partly because of the contrast between his views and Gödel's.