William Douglas was an influential American lawyer and politician, best known for his role as an Associate Justice of the United States Supreme Court. Appointed by President Franklin D. Roosevelt in 1939, he served on the Court for over 36 years, making him one of the longest-serving justices in history. Douglas was known for his strong advocacy of civil liberties and environmental protection. Throughout his career, Douglas was a prominent figure in the New Deal era, supporting various reforms aimed at improving the economy and social welfare. He was also an author, writing several books on law, politics, and nature, reflecting his deep commitment to both justice and the environment.