Kurt Gödel is regarded as one of the most outstanding logician of the twentieth century, famous for his work on logic and number theory. This third volume of a comprehensive edition of Godel's works comprises a selection of previously unpublished manuscripts and lectures. It includes introductory notes that provide extensive explanations and historical commentary on each of the papers. This book is accessible to a wide audience without sacrificing historical or scientific accuracy and will be an essential part of the working library of both professionals and students.