| In baseball, the shortstop is the player who defends the area between second base and third base.
The name "shortstop" comes from the fact that unlike today, in the very early days of baseball the second baseman covered the area on both sides of second base, whereas the "shortstop" was positioned just behind or to either side of the pitcher where he could field "short" balls, such as bunts and dribblers.
Defense
Shortstop is one of the most difficult, if not the most difficult, positions to play on the baseball diamond (perhaps second only to catcher), because he must have the greatest range, the strongest arm, the softest hands, and the quickest release of all the infielders. Because middle infielders must be right-handed to throw to first base, the shortstop is expected to cover not only his own area between second and third base, but also the no-man's land up the middle behind second base, because even though the second baseman could get to those balls almost as easily, he would not be able to make a throw to first base in time. The shortstop is also called upon to make the longest throw of any infield play - the long throw from the "hole" between himself and the third baseman - which sometimes has to be made after a dive from the grass in short left field. Moreover, since most batters are right-handed, and right-handed batters tend to hit balls to the left side of the infield, the shortstop handles more batted balls than any other player on the diamond. Finally, like the second baseman, the shortstop must have the agility to start or turn the double play, which requires him to race to the second base bag, step on it, and make an accurate throw to first base while leaping over an oncoming baserunner who is attempting to barrel over him. In short, the shortstop makes more plays, requiring stronger, more accurate throws, with less time to make those throws than any other infielder.
Getting a good defensive shortstop is probably the first priority for building a strong team, as he will make the whole team better with his play, lowering the ERA of the pitchers, allowing other infielders to cheat away from his area of the infield, making the first baseman look good with his strong, accurate throws, and allowing the outfielders to play a bit deeper by chasing down pop-ups in shallow left and center. It is no wonder that Leo Durocher once famously said, "Nobody ever won a pennant without a star shortstop."
For scoring purposes, the shortstop is denoted by the number "6" and thus one of the most common plays in baseball, a groundout to the shortstop, would be scored
6-3
Offense
Historically, a shortstop's defense was considered so important that so long as he was strong defensively, a shortstop was not expected to provide much offense, and good-hitting shortstops were relatively rare. However, beginning with Cal Ripken, Jr. in the 1980s, a cohort of young shortstops began to appear that were not only outstanding defensively, but were also among their team leaders in many offensive categories as well, such that nowadays, most shortstops are expected to make a fairly significant contribution on offense.
The Great Ones
Many of the finest players in baseball history have played shortstop. Among them are (Hall of Famers in bold):
Luis Aparicio - Luke Appling - Dave Bancroft - Ernie Banks - Dick Bartell - Mark Belanger - Lou Boudreau - Bert Campaneris - Dave Concepcion - Joe Cronin - Bill Dahlen - George Davis - Tony Fernandez - Nomar Garciaparra - Jack Glasscock - Travis Jackson - Hughie Jennings - Derek Jeter - Barry Larkin - Pop Lloyd - Rabbit Maranville - Johnny Pesky - Pee Wee Reese - Cal Ripken Jr. - Phil Rizzuto - Alex Rodriguez - Joe Sewell - Ozzie Smith - Vern Stephens - Miguel Tejada - Joe Tinker - Alan Trammell - Arky Vaughan - Omar Vizquel - Honus Wagner - Bobby Wallace - Willie Wells - Maury Wills - Robin Yount
Records
Career
Games played as a shortstop: 2583, Luis Aparicio
Home runs hit as a shortstop: 345, Cal Ripken, Jr.
Single Season (since 1900)
Games: 165, Maury Wills, 1962 Los Angeles Dodgers
Hits: 219, Derek Jeter, 1999 New York Yankees
Doubles: 54, Alex Rodriguez, 1996 Seattle Mariners
Triples: 21, Bill Keister, 1901 Baltimore Orioles
Home Runs: 57, Alex Rodriguez, 2002 Texas Rangers
Runs: 141, Alex Rodriguez, 1996 Seattle Mariners
Runs Batted In: 159, Vern Stephens, 1949 Boston Red Sox
Walks: 149, Eddie Joost, 1949 Philadelphia Athletics
Stolen Bases: 104, Maury Wills, 1962 Los Angeles Dodgers
Batting Average: .388, Luke Appling, 1936 Chicago White Sox
On-base Percentage: .491, Arky Vaughan, 1935 Pittsburgh Pirates
Most Gold Gloves, National League: 13, Ozzie Smith
Most Gold Gloves, American League: 9, Omar Vizquel
Baseball Positions
Pitcher - Catcher - First Baseman - Second Baseman - Third Baseman - Shortstop - Leftfielder - Centerfielder - Rightfielder - Designated Hitter | 
