It’s a much better use of your time and effort to have a hiring manager reviewing your résumé rather than a recruiter or human resources assistant. Mailing a letter directly to the hiring manager is smart for several reasons. First, they receive fewer résumés and may take more time in reviewing your credentials. Next, if there is a current hiring need, your background may catch the hiring manager’s attention, and Bingo! You’ve got yourself an interview. Alternatively, even if they aren’t currently hiring, many hiring managers keep a file of strong résumés.
True story: I was called for an interview for a position I later accepted after having sent my cover letter and résumé in to a hiring manager without any current needs, but based in my interest in working for that company. When an opportunity became available, my future colleagues reached for that manila folder stuffed with recent résumés and I was called in for an interview, even before HR was asked to source candidates. Knowing the position the best, the hiring manager sourced his own candidates.
The bottom line is that HR serves a purpose and is good at what they do, but if you’re taking the time to do a letter writing campaign, invest the extra time to identify the hiring manager and put your résumé in front of the decision maker.