Often times a job
listing does not include the name of the hiring manager. Never begin a
cover letter with "to whom it may concern" or “dear hiring manager.” A
generic salutation often signals to potential employers that you lack
the initiative to locate the appropriate contact.
Instead, call the company directly and explain the position you are
applying for to see if you can fill in the blank or take time to
research on the internet or in appropriate business periodicals to get
the name and title of the hiring official.