The Religious Society of Friends, also known as the Friends Church, is a Christian denomination. Members are known as Friends, or popularly as Quakers. There is a wide range of theological views including evangelical, conservative and liberal; collectively they differ from other churches by a particular emphasis on the doctrine of the priesthood of all believers. The Society is fragmented into autonomous local organisations, based on theological, social and cultural differences. Many of these groups hold strongly opposing views, leading to conflict. Worship varies between services co-ordinated by a pastor or recorded minister; or worship with no fixed programme which is predominantly silent.
The movement began in mid-17th century England when travelling preachers including James Naylor, George Fox, Margaret Fell and Francis Howgill broke away from the Church of England, bringing together groups of English Dissenters, attempting to restore what they believed were the practices of the early Church. They emphasised the idea that it was only Christ, rather than priests, who could speak to them.
Historically, Quakers have been known for their refusal to participate in war; plain dress; refusal to swear oaths; opposition to alcohol and participation in anti-slavery, prison reform, and social justice movements. Quakers are also known historically for founding and running a number of large corporations which were run under Quaker principles and have funded much of the Quakers' work - including banks (Barclays and Lloyds among others), financial institutions (eg Friends Provident), and manufacturing companies (eg Clarks, Cadbury, Rowntree, Fry's).
Source: Wikipedia, "Quakers", available under the CC-BY-SA License.