John Stuart Mill made significant contributions to political theory, particularly through his writings on liberty and utilitarianism. In his seminal work, "On Liberty," Mill argued for individual rights and the importance of personal freedom, emphasizing that society should not interfere with individual choices unless they harm others. His thoughts on women's rights advocated for gender equality and education, pushing for social reform. Mill's work on freedom of speech underscored the necessity of dissent in a healthy society. His ideas continue to influence contemporary discussions on politics and ethics.