The Zofingia Club was a discussion group to which C.G. Jung belonged as a medical student: in 1897 he became Chairman, and gave five lectures. These have survived and are published here in a supplementary volume to the Collected Works. The lectures are of great interest to anyone concerned with Jung's early ideas, as a young medical student from a strongly Swiss Protestant background. The Lectures are: The Border Zones of Exact Science (November 1896); Some Thoughts on Psychology (May 1897); An Inaugural Address on Becoming Chairman of the Zofingia Club; Thoughts on the Nature and Value of Speculative Inquiry (Summer 1898); and Thoughts on the Interpretation of Christianity with Reference to the Theory of Albrecht Ritschl (January 1899).