Immanuel Kant was a German philosopher who lived from 1724 to 1804. He is widely regarded as one of the most influential figures in modern philosophy and is known for his work in metaphysics, ethics, and aesthetics. Kant's most famous works include Critique of Pure Reason, Groundwork of the Metaphysics of Morals, and Prolegomena to Any Future Metaphysics. He is also credited with developing the concept of the categorical imperative, which states that an action should be judged based on whether it can be universally applied. Kant's philosophical ideas have had a lasting impact on modern thought and continue to be studied and discussed today.