“The Lord is my shepherd—shall be my motto of comfort and guidance.” With these words on his 23rd birthday, Henry A. Koch revealed a heart shaped by spiritual striving and vocational purpose. The Wauwatosa Diary opens a window into the soul of a seminary student during the formative years of the Wisconsin Synod’s Wauwatosa period. Spanning 1910–1912, Koch’s entries offer not only daily details of life at seminary but also intimate theological reflections and personal growth under the influence of J.P. Koehler, August Pieper, and John Schaller. Marked by both discipline and devotion, Koch’s decision to write daily in German evolves into a deeply introspective spiritual practice. From humorous anecdotes to critiques of sermons that fail to preach Christ, from academic rigor to moments of vulnerability, the diary reveals a young theologian in formation. Richly annotated, carefully translated, and illustrated with nearly 100 of Koch's own pictures, this edition offers scholars of Lutheran theology, German-American studies, and church history a rare primary source from the heart of a confessional tradition in transition.