The Pergamon application is always delivered with a top-level administrative user simply called 'admin' with the password initially set to 'password'. The 'admin' user should not be used on an every day basis however, and as such is configured with only a limited set of high-level administrative permissions. It should really be used as a backup-user which can be used to correct problems with other user accounts.
It is far better to create a new everyday working user for each librarian or library assistant (i.e. a member of staff, not a trusted reader assistant) and provide them with the appropriate permissions to do their job.