The first modern American president, Theodore Roosevelt (1858-1919) was also one of the most popular, important, and controversial. During his years in office he greatly expanded the power of the presidency.

A strong nationalist and a resourceful leader, Theodore Roosevelt gloried in the opportunities and responsibilities of world power. He especially enlarged the United States role in the Far East and Latin America. At home he increased regulation of business, encouraged the labor movement, and waged a long, dramatic battle for conservation of national resources. He also organized the Progressive party (1912) and advanced the rise of the welfare state with a forceful campaign for social justice.

Roosevelt was born in New York City on Oct. 27, 1858. His father was of an old Dutch mercantile family long prominent in the city's affairs. His mother came from an established Georgia family of Scotch-Irish and Huguenot ancestry. A buoyant, dominant figure, his...