Augustin-Louis Cauchy brought formalism to mathematics in the 19th century and defined the concepts of limits, continuity, and derivatives, familiar to modern-day students of calculus. He made contributions to number theory, developed ideas on the convergence of infinite series, and contributed to the field of astronomy. Cauchy's most significant contribution to mathematics, however, is as the co-founder, along with Karl Gauss, of complex analysis.

Less than two months after the fall of the Bastille, on August 21, 1789, Augustin-Louis Cauchy, the son of Louis-France Cauchy and Marie-Madeleine Desestre, was born in Paris. It was a time of great turmoil in France, and Cauchy's father, having served the recently overthrown monarchy as a parliamentary lawyer and a lieutenant of police, thought his new family would be safer if they moved to the countryside. Shortly after Cauchy's birth, they took up residence in the village of Arceuil. Cauchy spent the first 11 years...