Leonard Boudin was an influential American civil rights attorney known for his work in the mid-20th century. He played a significant role in various landmark cases that addressed issues of free speech, civil liberties, and social justice. Boudin was associated with the American Civil Liberties Union (ACLU) and was a prominent figure in defending unpopular causes. Boudin was also the father of Michael Boudin, a federal judge, and his family has a legacy of involvement in law and civil rights. His commitment to justice and advocacy for the marginalized left a lasting impact on the legal landscape in the United States.