Jean le Rond d'Alembert was an 18th-century French mathematician, philosopher, and physicist, best known for his contributions to the fields of mathematics and mechanics. He co-edited the influential Encyclopédie, which aimed to compile and disseminate knowledge during the Enlightenment. His work in mathematics includes the formulation of the d'Alembert principle, which is fundamental in the study of dynamics. In addition to his mathematical achievements, d'Alembert made significant contributions to wave theory and probability. He also explored philosophical ideas, particularly in relation to the nature of knowledge and reason. His legacy continues to influence various scientific disciplines today.