 Bolzano’s uncommonly versatile work culminated in three extensive main writings in three different areas of knowledge: (1) in theology his four volume Textbook of the Science of Religion (Bolzano 1834), (2) in philosophy the four volume Theory of Science (Bolzano 1837), which provides a new foundation for logic and is at the same time an extensive manual of logic, and (3) in mathematics the Theory of Quantities, conceived of as a monumental work, but not completed.