Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Leonard Hilburne Gabrielson (8 September 1915 14 November 2000) was a first baseman in Major League Baseball who appeared in 5 games for the Philadelphia Phillies during the 1939 season. Gabrielson's son, also named Len Gabrielson, spent 9 seasons in Major League Baseball. Major League Baseball (MLB) is the highest level of professional baseball in the United States and Canada, consisting of teams that play in the National League and the American League. The two leagues merged in 2000 into a single MLB organization led by the Commissioner of Baseball after 100 years as separate legal entities.