What is a casting director?
It is the casting directors responsibility to find actors to audition for casting directors and or producers. Casting directors must stay in contact with actors, agents and managers in order to have a wide variety of talented actors at their disposal. In order to be placed in a casting directors files you must contact and send them your head shots and resume. You may also want to meet and interveiw with them, especially if you live close.
Why should you contact them?
As a professional actor you should take it upon yourself to submit your resume and head shots to all the casting directors that you can. This will definately increase your chances of getting the role. Imagine if you or your agent received a call from a casting director that had your resume and head shots on file. It is true that most casting director check their files to see if anyone matches the part first. You should be in their files.