Stephen Cole Kleene was an American mathematician and logician, known for his significant contributions to the fields of mathematical logic and theoretical computer science. Born on January 5, 1909, he developed important concepts such as Kleene algebra and regular expressions, which are fundamental in computer programming and automata theory. Kleene earned his Ph.D. from Princeton University in 1934 and later became a professor at the University of Wisconsin-Madison. His work laid the groundwork for many areas in computer science, influencing how computers process and understand languages. Kleene passed away on January 25, 1994, leaving a lasting legacy in mathematics and computer science.