1. Lefty GroveOne of the most underappreciated pitchers in baseball history. Others have more wins - Grove won his 300th game in his final start of a 17-year career - but in other areas, he was unparalleled. He led the American League in strikeouts seven consecutive years, victories four times and ERA nine times. If he had played in an era with the Cy Young Award, he would have won it as much as Roger Clemens. Grove did win the MVP award in 1931, when he went 31-4 with a 2.06 ERA and five saves to boot. He also has two World Series wins, and went 4-2 with a 1.75 ERA in the postseason in his career.
2. Warren SpahnNobody was as good for as long as Spahn, who won 363 games, tops among lefties. He won 357 of them for the Boston/Milwaukee Braves from 1946-64. He pitched for 21 seasons, and went 23-7 at age 42. He was a 14-time All-Star, had an astounding 382 complete games and career ERA of 3.09. He led the league in strikeouts four times, won four World Series games and had two career no-hitters.
4. Sandy KoufaxWhile Spahn, Grove and many of the others were greater for longer, no pitcher was better - ever - than Koufax was in the final six years of his career for the Dodgers. He went 129-47 and won three Cy Young Awards, leading the league in strikeouts four times. He whiffed 382 in 335 2/3 innings in 1966. He won three World Series rings with Los Angeles, and went 4-3 with an 0.95 ERA in eight World Series appearances. He was a supernova, retiring at age 30 after the 1966 season with a left arm that was already out of gas.
5. Whitey FordOn a team full of great players, sometimes Whitey Ford gets lost. But as one of the finest pitchers of the great 1950s-1960s Yankees teams. he stands on his own. Ford won one Cy Young Award - going 25-4 in 1961 - and collected 236 wins in 16 seasons. His career ERA of 2.75 is even better than Sandy Koufax - bet you'd win a bet with that. He was a consistent winner on some great teams, and won 10 World Series games, which is the best of any player in the pre-divisional era (when there only was the World Series, no playoffs).
7. Carl HubbellHubbell is best remembered for striking out Babe Ruth, Lou Gehrig, Jimmie Foxx, Al Simmons and Joe Cronin in succession in the 1934 All-Star Game. But the New York Giants lefty was pretty good the rest of the time, too. In a Hall of Fame career, he went 253-154, with an ERA (2.98) better than Grove, Johnson, Spahn and Carlton. He won more than 20 games every season from 1933-37 and was named MVP in 1933 and 1936, but fizzled out in the final six years of his career.
8. Tom GlavineWith 305 victories after being cut by the Atlanta Braves in 2009, he might be the last left-hander with 300 wins for a long time. He won 20 or more games five times, had two Cy Young Awards and compiled a solid career ERA of 3.54.
9. Eddie PlankThe best lefty of the dead-ball era, he won 20 games eight times and had 326 wins in 17 seasons for the Philadelphia A's. The only person with more wins on this list is Warren Spahn. He won four pennants with the A's, part of a great pitching staff that included Chief Bender and Rube Waddell.
10. Babe Ruth
This might be a controversial pick, as he won just 94 games on the mound. But, like Koufax, no left-hander was better in a short period - his was 1915-18 before he became the greatest power hitter in baseball history. He went 23-12 with a 1.75 ERA in 1916 at age 21 for the Boston Red Sox, and finished his pitching career with a 94-46 record and a 2.28 ERA, the best on this list. He even pitched a complete game win for the Yankees at age 38 in 1933.