Trade unions are associations established for the purpose of maintaining or improving the conditions of the working lives of wage earners. Although some contemporary unions may trace their origins to the medieval guilds, the present day form of trade unions primarily is the result of the Industrial Revolution and the large wage-earning class which it created. Unions exist in almost every contemporary nation-state, where they are typically considered to be a principal representative of the interests of employees.

There are different varieties of union, but most can be categorized as falling into one of two types: social democratic unions, which have a strong political function and are often associated with a labour or socialist political party, and business unions, which are purely unions of workers without strong political interest. One of the most important tasks of the union is collective bargaining for workplace conditions and terms of employment on behalf of union members. The right to strike remains the primary basis of union power.

The contemporary era has been difficult for trade unions, with declining membership and harsher legislation in at least some developed countries. However, they continue to be an important feature of most nations, and are generally considered to be a fundamental pillar of democracy. They are likely to continue to play a significant role in society.

Roy Adams