Drupal Workflow
Description
Workflows are made up of workflow states. Transitions between states can be allowed per role. For example, a workflow with the states Draft, Review, and Published could be assigned to the Story node type. Only users with role 'chief editor' can set Stories to the published state. You can set up the Workflow to alter states from form, page, comment, a special block, and a special workflow tab. Additionally, the submodule Workflow Access allows you to manage view/edit/delete permissions for content types per User role and Workflow state.
Transitions between workflow states can have actions assigned to them. In our example, we could assign an action so that when the story moves from the Draft state to the Review state an email is sent out. Another action could be assigned to the transition from Review to Published so that the node's status is set to Published (and becomes visible on your website).