Carl Schmitt's library is brinuntng with thousands of books that are unrelated to political theory and constitutional law, the main topics of his work. 'There is almost no field in which he does not own a significant number of books: from poetry to terrorism and revolutionary writings to Spanish History and theology. The fact that inany of these books are filled with underscoring and handwritten remarks makes this library a very valuable source for uncovering Schmitt's opinions on subjects about which he has not published. In this article I analyze the marginalia that Carl Schmitt devoted to the most important Spanish language writer of the 20th century. The German author found in Jorge Luis Borges not only an enemy, on account of his philo-Semitisin and liberalism, but also an unexpected soul mate.