When it comes to the topic of cover letters, today there's no such thing as conventional wisdom. A quick Internet search turns up many comments from job seekers who are glad to see it go and career experts who say, "Toss it." But some people still advise, "Better write a good one; they're important."

I fall into the latter camp—but I do recognize that the role of the cover letter has changed. No longer do you introduce your resume or industry CV with a letter on the finest linen stationary; the letter will be printed out, if at all, on whatever paper the human resources (HR) department  happens to have in the printer. And it's true that a lot of people don't even read cover letters.

Yet, the cover letter still serves a purpose that no other part of your application package can serve: It makes a strong, upfront, specific case for your candidacy for the position. There's no better opportunity—at least until the interview—to point out a particular strength or hammer home the reasons you'd be an especially good fit for the position.

Why bother?

You might well ask, "Why are cover letters necessary? I just filled out six online applications and not one company required it." If you're applying online, a cover letter may not be necessary, but it's still a good idea. It's an opportunity to personalize your application. Will your letter be to an HR person? A hiring manager? If you are applying via a Web site, you probably won't know who to write to; you'll be stuck writing a "To Whom it May Concern" letter if you get to include one at all. But, when working your network, as we advise so often at Science Careers, you'll be able to e-mail people directly and include a nicely formatted Microsoft Word or PDF document addressed to them personally. That's the best approach.

Writing a letter also forces you to consider the uniqueness of the opportunity in front of you. You start to differentiate yourself, to focus on what you can do for them, and to sell that to the company. You should never use a "generic" cover letter that fails to make specific reference to a particular job or reader.

Another reason why a cover letter is good is that it allows you to present your strengths and accomplishments in bite-sized nuggets. That's both good practice and an effective job-search strategy. I wrote about the importance of succinct writing in part one of this series; the cover letter should carry that forward. You will, in fact, utilize one of those "Challenge-Approach-Results" (C-A-R) paragraphs from part one later in this column. But before we get to that, I'll talk about how cover letters can be an advantage to employers—even if, as you may have discovered, they don't ask for them very often.

How is the cover letter received?

Just because you've written a great cover letter doesn't mean that everyone is going to read it. I did an impromptu survey of my HR friends; just 40% told me they "regularly" read the cover letter. The other 60%, though, said that they read cover letters on occasion, and that in certain situations a cover letter could be very useful.

Andrea Piccarelli, manager of human resources at The Smithers Group in Akron, Ohio, tells me that while she doesn't consistently read them, cover letters are important in several situations. "For example, if I look at the CV but notice the home address isn't in the geographical area of our business, I will go to the cover letter to see what the applicant had to say about the potential of actually making a move," Piccarelli says in an interview.

"In another instance, there may be a very strong emphasis on communication skills for a particular job, and there's no better way to get a grasp on that than to see how they write their cover letter. Lastly, if there's a significant gap in employment—or perhaps a series of short stays in jobs—I want to see an explanation there in the cover letter."

The mechanics of writing the cover letter

The passage of time is most obvious in the cover letter's changing format and appearance. No one opens a physical envelope anymore, and even the fax has mostly vanished. Your choice, then, is whether to work up a nicely formatted Microsoft Word or PDF version and incorporate it as page one of the CV—or, as most people do, separate them into two separate documents. If you're applying online, you'll probably just paste your cover-letter text into a box.

Piccarelli offers another option: She says that, if you're sending your package by e-mail, it's OK to put your cover-letter points in the e-mail that encloses the CV, and many people would agree with her. Unfortunately, not everyone prints out the email when they circulate an enclosure. Take me: If I want to hand my client a binder of our candidates for a search, I'll routinely print cover letters and CVs, but I never print an e-mail. If you want to ensure that everyone reads your covering statements, you stand a better chance with a separate, stand-alone document.

Consider the cover letter your first piece of eloquent business writing. It's a sales tool. It is not meant to be a restatement of what is in your CV, or a multipage ramble on what you've done at work and what you want out of life. The cover letter should be a clearly written, succinct, three-paragraph summary that teases the reader into wanting to know more about you. It's formulaic, or should be.

Paragraph One. This is where you explain how you and the reader are connected. "You'll recall that we met at the PAG 2013 meeting in San Diego where we had a cup of coffee with our mutual friend Dan." Or, "I saw the advertisement for a senior scientist in your process development team and wanted to draw your attention to my CV." I don't think you should ever write a "To Whom it May Concern" letter, but you may not be able to avoid it if you are applying via their online application process.

Paragraph Two. This is the critical paragraph, where you bring out the big gun—your most relevant accomplishment—and entice the reader to look at your CV. In part one of this article I told you how to write a succinct statement about your accomplishments, via the C-A-R exercise. Here's where you put that to use. "I'm sure that the scientist you hire for process development will need to have great critical-thinking skills to aid the company's program in microbial process development. I demonstrated such skills, to cite one example, after my boss asked me to resolve a problem where a bench-scale E. coli fermentation had dropped 20% in yield, suddenly and without apparent cause. My approach was to take it back to shake flasks and do a bioanalytical study. I found a way to improve the media and we were able to get the process up and running again, with a 7% increase in throughput for the secondary metabolite of interest."

Paragraph Three. In marketing circles, this is known as the "call to action." Whether you are writing a Web page for a product or a cover letter for an employment package, the call to action provides critical closure for your message. Marketing experts will tell you that the key to a call to action lies in its simplicity, so don't overdo it. The goal is to suggest what should happen next: "I would love to have an opportunity to meet with you or your HR business partner, in person or by phone, to discuss your company's needs and my fit with those needs. Alternatively, I'll be in Boston next month for the American Society for Microbiology meeting; I'll check in with you beforehand to see if we can meet." If there are any "issues" with your CV—a long gap due to illness, parenting, or unemployment, for example—this is the paragraph where those should be defused.

That's all you need: three simple paragraphs, fine-tuned to make the best possible impression and illustrate that you match the employer's requirements. Whether it is an e-mail or, better, a nicely formatted Microsoft Word document or PDF, don't miss this opportunity to reinforce your fit to the job, or to clarify some issue that otherwise might scare people off. While it may not be as important, or as widely read, as it once was, the cover letter remains an important tool in finding a job.

A writer and speaker on career issues worldwide, David Jensen is the founder of CareerTrax Inc. and managing director of Kincannon & Reed Global Executive Search.

10.1126/science.caredit.a1300202