As of this writing, third baseman Miguel Cabrera of the Detroit Tigers is one home run shy of leading (or being tied for the lead in) the American League in batting average, home runs, and runs batted in (RBI). Historically, these three categories have constituted the batting Triple Crown, and it is a mark of this rarity that only 14 hitters in baseball history, 11 of those during the modern era begun in 1901, and only 9 of those during the live-ball era begun in 1920, have ever accomplished this feat, which signifies the ability to hit for average, hit for power, and produce runs. In the current sabermetrics era, both batting average and RBI are considered to be overvalued as measurements of ability and effectiveness, yet of the 14 men who have accomplished this, 12 are in the Hall of Fame. Coincidence? Let's see.
Pitching also has its Triple Crown, for (starting) pitchers who lead their league in wins, earned run average (ERA), and strikeouts, and although wins have also been discounted by sabermetricians as a measure of a pitcher's effectiveness—a "win" is composed of many factors contributed by the team—both ERA and strikeouts are still very much indicators of a pitcher's effectiveness. Last year both the Los Angeles Dodgers' Clayton Kershaw, for the National League (NL), and the Tigers' Justin Verlander, for the American League (AL), were Triple Crown winners, the first time since 1924 that each league had a pitching Triple Crown winner in the same year; not surprisingly, both Kershaw and Verlander won their league's respective Cy Young Awards, with Verlander also winning the AL Most Valuable Player Award—quite an unusual honor for a pitcher. (For the record, in 1924 the Washington Senators' Walter Johnson was the AL pitching Triple Crown winner, while the Brooklyn Dodgers' Dazzy Vance was Johnson's NL counterpart.)