Roles are being used to group Users to facilitate the assignments of what users are allowed to view and manage. These rights can only be assigned on the Role level.
For example, you can allow members of the Economy Role have access to a specific Invoice Log Views.
Any number of application Roles can be defined.
You must be member of the Administrators role to manage Roles (and all other administrative parts/objects).
There is a special role named Administrators. This role cannot be renamed or deleted. See Authorization for additional details.