Control editing/visibility of individual fields by role.
As well as custom settings ('create own', 'edit own', 'view own', 'edit any' and 'view any' - all per role), there's a Private setting which gives access to the author and administrator only.
These are automatically applied to views.
Finding the setting: Look for Field visibility and permissions – on the Edit tab, NOT Field Settings.
In /admin/people/permissions there's also a Access other users private fields permission.