Sell Yourself

• A hiring manager will receive any number of resumes for a new job opening. And since all resumes look similar at first glance, your cover letter is a place you can highlight your individuality. Here you can tell the story of yourself; you can communicate that you're upbeat, positive and confident, and that you're ready to take on new challenges. The cover letter is your best chance to make a positive and lasting first impression.
  
  

Emphasize Your Strengths

• A cover letter also allows you to emphasize the strengths listed in your resume that are particularly important to the job you're applying for. Because you can't always fit everything you'd like to in your resume, your cover letter is the place to expand on your strengths with details that demonstrate your abilities. Share anecdotes that paint a picture of what you've accomplished for the reader.
  
  

Professionalism

• Submitting a resume without a cover letter is like meeting a new business partner without a handshake. A cover letter not only introduces you to your prospective employer and allows you to emphasize your strengths, but it also demonstrates that you understand the way a professional workplace works. It demonstrates an attention to detail and a willingness to do things right on your part, whereas the absence of a cover letter may convey to a hiring manager laziness or a lack of attention to detail.
  
  

Communication Skills

• Your cover letter says more than simply the words it contains; it's also an example of your writing style and abilities. An articulate, well-written cover letter can communicate that you employ clear thinking and communication in your work, while a poorly-written one may suggest a worker who thinks or communicates poorly. The tone and style of your letter are intangibles that the reader will use to characterize you as an applicant.
  
  

Explaining Potential Red Flags

• Hiring managers will be wary of red flags in your resume; employment gaps between jobs or having changed jobs frequently can signal that you're not a long-term employee. But a cover letter gives you the opportunity to dispel questions before they arise by explaining why those gaps exist, why you suddenly changed careers, or why you're searching for a job while you already have one.