Johann Heinrich Tieftrunk belongs to the group of true Kant-followers of the 'closed Kantian' ('geschlossen kantische') period [Gerhard Stammler] of earlier Kantianism in Halle (approx. 1770-1817). Except for his philosophy of religion, his philosophical work has thus far been ignored. Significant in this regard is our lack of biographical data on Tieftrunk. Some puzzles, however, such as his date of birth, have now been solved.