"For the problem of the Twentieth Century is the problem of the color line." W.E.B. DuBois, from the introduction to The Souls of Black Folk (1903)
The color line was a de facto rule in major league baseball from 1884 until 1946. It is also commonly referred to as the color barrier. Owners in the major leagues colluded to ban players who were of African descent. This ban also extended to dark skinned players of Latin descent. The issue was not limited strictly to baseball, but was a fact of life faced by African Americans in all walks of society at the time.
After World War II, the Brooklyn Dodgers breeched the color line with the signing of Jackie Robinson in 1946. When Robinson made his debut with the Dodgers on April 15, 1947, he broke baseball's color barrier and the slow process of integration in major league baseball began. Larry Doby broke the color barrier in the American League on July 5, 1947.
Certain Latin players, although they played in the Negro Leagues, were light-skinned enough to also play in the white major leagues and did in the early years of the 20th century.
- Chris Lamb: Conspiracy of Silence: Sportswriters and the Long Campaign to Desegregate Baseball, University of Nebraska Press, Lincoln, NE, 2012.
- Roberta Newman: "Pitching Behind the Color Line: Baseball, Advertising, and Race", in The Baseball Research Journal, Number 36 (2007), SABR, Cleveland, OH, pp. 81-90.
- Ryan A. Swanson: When Baseball Went White: Reconstruction, Reconciliation, and Dreams of a National Pastime, University of Nebraska Press, Lincoln, NE, 2014. ISBN 978-0-8032-3521-2