Voluntaryism is the belief that all
interaction should be voluntary and, by necessity, free of external coercion. It is heavily related to te NAP due to it's rejection of initiating force against others while still allowing for defensive actions.
Another key aspect to voluntaryism is self ownership: each
individual owns him/herself and is therefore
responsible for their own actions. Furthermore, no person or group has any legitimate claim to excersizing control over, or otherwise placing restraints on, the actions of others so long as the person's actions do not violate the equal rights of others.