Labor unions are credited with advancing the cause of the working class in the 20th century. Although membership is currently in decline, labor unions were once immensely powerful organizations; unions gave bargaining power to workers and forced company owners to share political influence. Vast systemic economic shifts have helped reduce the influence of unions in the 21st century.
Labor unions have their roots in guilds of Europe during the Middle Ages. In the United States, craft unions of the 18th and 19th centuries gave way to the dominance of organizations like the American Federation of Labor (AFL) and the Congress of Industrial Organizations (CIO) in the 1930s.
Unions feature a membership, which pays dues. Union organizers hold votes on contracts and elect officers and other representatives, who help to negotiate terms with employers. Unions also organize strikes when contract negotiations break down.
The rise of labor unions paralleled the increase in factories and production lines in the 1900s. Especially in the manufacturing and transportation industries, labor unions rode the Industrial Revolution to prominence.
Labor unions have traditionally won concessions for workers. These benefits include shorter working hours, days off, safer working conditions, and increased pay and health coverage.
Some of the labor movement's most famous figures include the AFL's first president Samuel Gompers, Teamsters president James Hoffa and women's labor activist Mabel Gillespie.
As the Industrial Era has given way to the Information Age, the 21st century has seen union membership decline steadily. This is because of a movement to a service-based economy; despite organization efforts, service industries simply have not unionized the way manufacturing and transportation once did.