The philosophical work of Sir Karl Popper differs strikingly from others by its wideness of scope. It covers, among other things, the methodology of science, logic, political science, history, probability theory, psychology, and the histories of science and philosophy. Sir Karl has many followers working in very different disciplines who, consequently, do not always understand each other. What might be called “the Prague appreciation of Sir Karl” was initiated by medical doctors, with a weak philosophical background, who were interested primarily in his thoughts regarding the self and its brain. But analytical philosophers, mathematicians, sociologists, and political scientists in Prague were interested in what George Soros, in his address at the Central European University, called “a totally different aspect of his work.”1 But despite his wide-ranging philosophical interests, Sir Karl’s thought shows considerable consistency, closely related to his “clarity, beauty and kindness.” What is the reason for the prima facie thematic breadth of his work? In my opinion it is the inability of scholars like me to match his universality and his exceptional capacity to apply general ideas in seemingly independent areas. Let me share with you the rather private delight that I experienced in discovering a common denominator in Sir Karl’s notes on induction and demarcation of science (Popper 1980; Popper and Eccles 1977) on the one hand, and his fight against historicism (Popper 1957) in political science on the other.