Practically all types of industries have started as private business. But only a few have remained absolutely free. The usual case is that certain types of restriction and introduced by trade organisations, by local authorities, or more often, by the state. These restrictions take various forms: - Regulation, so that certain types of behaviour are deemed unlawful; - Control, so that you have to obtain permission to act in a specific way; - Authorisation, so that you have to obtain a permit to operate within a specific trade; - Socialisation, i.e. private business taken over by the state.