Gustavus E. M. de la Vallée Poussin was a Belgian mathematician born on March 14, 1866, and he passed away on December 2, 1962. He is best known for his contributions to the field of mathematics, particularly in number theory and analysis. His work laid the groundwork for various mathematical concepts that are still relevant today. In addition to his research, de la Vallée Poussin was a prominent educator, teaching at several universities. He was also involved in the development of mathematical education in Belgium and contributed to the promotion of mathematics as a discipline. His legacy continues to influence mathematicians and educators alike.