Steven Norman Carlton (born December 22, 1944), nicknamed "Lefty", is a former Major League Baseball left-handed pitcher. He pitched from 1965 to 1988 for six different teams in his career, but it is his time with the Philadelphia Phillies where he received his greatest acclaim as a professional and won four Cy Young Awards. He was elected to the Baseball Hall of Fame in 1994. Carlton has the second-most lifetime strikeouts of any left-handed pitcher (4th overall), and the second-most lifetime wins of any left-handed pitcher (11th overall).

Following a salary dispute, Cardinals owner Gussie Busch ordered Carlton traded. Eventually, he was traded to the Philadelphia Phillies before the 1972 season for pitcher Rick Wise.  The trade is now considered one of the most lopsided deals in baseball history. However, at the time, the trade appeared to make sense from the Cardinals' perspective. Carlton had won 77 games to Wise's 75, and both were considered among the game's best pitchers. Tim McCarver, who had caught for Carlton in St. Louis and for Wise in Philadelphia, described the trade as "a real good one for a real good one." He felt Carlton had more raw talent, but Wise had better command on the mound. Although Wise would stay in the majors for another 11 years (though only two of them were with the Cardinals), the trade is now reckoned as an epoch-making deal for the Phillies, as well as one of the worst trades in Cardinals history.  In Carlton's first season with Philadelphia, he led the league in wins (27), complete games (30), strikeouts (310), and ERA (1.97), despite playing for a team whose final record was 59-97. His 1972 performance earned him his first Cy Young Award and the Hickok Belt as the top professional athlete of the year. His having won 46% of his team's victories that season is a record in modern major league history. Carlton attributed his success to his grueling training regimen, which included Eastern martial arts techniques, the most famous of which was twisting his fist to the bottom of a 5-gallon bucket of rice.  Some highlights of Carlton's 1972 season included starting the season with 5 wins and 1 loss, then losing 5 games in a row, during which period the Phillies scored only 10 runs. At this point he began a 15-game winning streak. After it ended at a 20-6 record, he finished the final third of the year with 7 more wins and 4 losses, ending with 27 wins and 10 losses. Carlton also completed 30 of 41 starts.  During the 18 games of the winning streak (3 were no-decisions), Carlton pitched 155 innings, allowed 103 hits and 28 runs (only 17 in the 15 winning games), allowed 39 walks, and had 140 strikeouts. From July 23, 1972 to August 13, 1972 he pitched five complete game victories, allowed only 1 unearned run while only giving up 22 hits in 45 innings, and threw four shutouts. He had a fastball, a legendary slider, and a long looping curve ball; and later a change-up, then a screwball. Baseball commentators during 1972 regularly remarked that Carlton's slider was basically unhittable, while Pittsburgh Pirates slugger Willie Stargell once remarked, "Hitting Steve Carlton's slider is like trying to drink coffee with a fork". He was also a good hitter for a pitcher; at times he pinch-hit for the Phillies during 1972.

Was the trade a positive thing for Carlton?
The trade is now considered one of the most lopsided deals in baseball history.