Acknowledgments.- Note on citation and translation.- 1. Introduction: Kant on Science and Biology.- 2. Kant\'s Conception of Proper Science.- 3. Mechanical Explanation and Grounding.- 4. Kant on Teleology.- 5. Kant on the Domain and Method of Biology.- 6. Kant on the Systematicity of Physics and the Opus postumum .- 7. Vital Forces and Organisms in the Opus postumum .- 8. Materialism, Hylozoism, and Natural History in the Opus postumum .- 9. Concluding Remarks.