Bertrand Russell (1872–1970) was a British philosopher, logician, mathematician, historian, and social critic, widely regarded as one of the founders of analytic philosophy. His work in logic, particularly Principia Mathematica, co-authored with Alfred North Whitehead, laid the groundwork for modern mathematical logic. Beyond philosophy, Russell was an outspoken advocate for education, free thought, and social reform. He was a critic of war, opposing World War I and later campaigning against nuclear weapons. His writings, including A History of Western Philosophy, The Conquest of Happiness, and Why I Am Not a Christian, continue to influence philosophical thought, ethics, and political discourse. Awarded the Nobel Prize in Literature in 1950, Russell's legacy remains one of intellectual rigor, humanitarian ideals, and fearless advocacy for reason and progress.