Oswald Külpe (; 3 August 1862 – 30 December 1915) was a German structural psychologist of the late 19th and early 20th century. Külpe, who is lesser known than his German mentor, Wilhelm Wundt, revolutionized experimental psychology at his time. In his obituary, Aloys Fischer wrote that, “undoubtedly Külpe was the second founder of experimental psychology on German soil; for with every change of base he made it a requirement that an experimental laboratory should be provided.” Külpe studied as a doctoral student and assistant to Wundt at the University of Leipzig, though his ideas differed from Wundt as he developed his own research (Boring, 1961). Külpe made significant contributions to the field of psychology, some of which are still relevant, including the systematic experimental introspection, imageless thoughts, mental sets, and abstraction. Biography In August 1862, Oswald Külpe was born in Kandau, Courland, one of the Baltic providences of Russia. However, his father, a notary, and his mother were German. Consequently, Külpe’s native tongue was German. He had a brother, Alfons Külpe who was a clergyman, and a sister who was a nurse. He lived a large portion of his life with his older, unmarried cousins, Ottillie and Marie Külpe, at their residences in Leipzig, Würzburg, Bonn, and Munich. He never married either and throughout the years he devoted an immense amount of time to his work. It was said that Külpe would joke that science was his bride. He learned Russian during his training at the Gymnasium in Libau, where he graduated in 1879. He then taught history and other subjects at a boys’ school for a year and a half before relocating to Leipzig. In 1881 he enrolled in the University of Leipzig. He focused his studies mostly on history, however he attended the lectures of Wilhem Wundt. In these he became familiar with the blossoming field of psychology, the area upon which his life work eventually would be focused. In between 1882 and 1883, Külpe studied at the University of Berlin, where he attended the lectures of Heinrich von Treitschke, a nationalist German historian. Following his studies in Berlin, he transferred to Göttingen, where he spent two years as a student of Georg Elias Müller, where it is said he received the idea for his doctoral dissertation. Following his time with Müller, he returned to Leipzig to study under Wundt as his assistant in the autumn of