René Laennec was a French physician born on February 17, 1781. He is best known for inventing the stethoscope, a medical instrument that allows doctors to listen to the internal sounds of a patient's body, particularly the heart and lungs. His invention revolutionized the practice of medicine and improved the diagnosis of various diseases. Laennec published a significant work titled De l'auscultation médiate in 1819, which detailed his findings and techniques related to auscultation, the process of listening to body sounds. His contributions laid the foundation for modern clinical examination and greatly advanced the field of pulmonology. Laennec passed away on August 13, 1826.