Softball is a team game that is a direct descendant of baseball. The main differences are that softballs are larger than baseballs, the pitches are thrown underhand rather than overhand, and softball is played on a smaller diamond than baseball. Rule variations include restrictions such as baserunners being required to keep one foot on a base until the pitcher throws the ball or until the ball crosses the front edge of home plate. Some slow pitch associations allow for an extra fielder.
The earliest known softball game was played in Chicago, Illinois on Thanksgiving Day, 1887 as an indoor winter alternative to baseball. The first balls were boxing gloves tightened into balls. George Hancock is credited as the game's inventor for his development of a 17" ball and an undersized bat. The Farragut Club set down rules for the game, and it spread quickly. Early on, the sport was called "Indoor Baseball". In 1895 Lewis Rober, Sr. of Minneapolis, MN organized outdoor games as exercise for firefighters. Rober's version of the game used a ball 12 inches in circumference which soon became the norm for the sport. The name "softball" dates to 1926 when it was coined by Walter Hakanson of the YMCA. The formation of the Joint Rules Committee on Softball in 1934 standardized the rules and naming throughout the United States.
There are two main variants of the game - fast pitch and slow pitch softball. Women's fast-pitch softball debuted at the 1996 Olympics. The International Olympic Committee voted to drop softball and baseball as Olympic sports for the 2012 Summer Olympic Games, but it made a return at the 2020 Olympics in Tokyo, alongside men's baseball.
The International Softball Federation holds world championships every four years in various categories. The ISF is the international governing body for the sport. The Amateur Softball Association is the National Governing Body of Softball for the United States pursuant to the 1976 Amateur Sports Act. There are many governing bodies such as the United States Specialty Sports Association, International Softball Congress and the National Softball Association.
Softball is an extremely popular team sport in the United States. It is estimated that 40 million Americans will play at least one game of softball during any given year. It is played by both men and women both recreationally and competitively. In interscholastic leagues, it is almost exclusively a female sport. Softball is played, at some level, in over a hundred countries around the world. The International Softball Federation has 113 member countries.
In many US cities, adult softball teams are organized by bars and clubs, hence the popular term "beer-league softball". The teams can be men's, women's or co-ed, and skill levels can range from novice to elite, with league composition reflecting that. These leagues are almost exclusively slow-pitch.
Professional leagues have been attempted with varying degrees of success. The sport has produced a number of stars including Eddie Feigner of the King and his Court fame and Olympian Jennie Finch who is married to Major League pitcher Casey Daigle. Broadcaster Jessica Mendoza is another former elite softball player.
Many female baseball players came from a softball background, while in some countries such as Belgium, a fair number of male baseball players also have played softball.
- Mark Allister: Women’s College Softball on the Rise: A Season Inside the Game, McFarland, Jefferson, NC, 2019. ISBN 978-1-4766-7616-6
- Chris Landers: "The story of the Ivy Leaguers who used their Thanksgiving to invent the sport of softball", "Cut4", mlb.com, November 21, 2017. 
- Independent Softball Association (ISA)
- International Softball Congress (ISC)
- Amateur Softball Association (ASA)
- Chicago 16 Inch Softball Hall of Fame
- National Softball Association (NSA)
- United States Specialty Sports Association (USSSA)
- Softball Canada
- Softball Australia
- Great British Baseball and Softball Governing Body
- Irish Softball Association
- German Slowpitch Portal
- National Wheelchair Softball Association
- Softball in Ecuador
- South Asian Softball
- Danish Softball Federation