There was a guy in my writing class who wrote hilarious essays about the impact of Asperger’s syndrome on his marriage. This was years ago when articles about autism were everywhere, but Asperger’s was its distant, lesser-known cousin.

In story after story, he recounted his wife’s dismay as he passed up yet another gas station because it had an odd number of pumps. Or how he would take hourlong showers every morning — reciting the ingredients from the shampoo bottle — while she took care of their two toddlers. And how he would grill her on the exact time they would be done with Thanksgiving dinner at her aunt’s house — not because he had anywhere to go, just because he needed to know.

“You have to get these stories into Modern Love,” I told him one night after class.

“Modern Love? What’s that?” he asked.

He wasn’t familiar with The New York Times’ personal essay column about the “joys and tribulations of love.” He was an electrical engineer busy making sure he had the exact right number of blueberries on his breakfast cereal. So, I briefed him on the column, which appears in the paper’s Style section every Sunday, and sent him a link to one of my favorite Modern Love essays, What Shamu Taught Me About a Happy Marriage.

From there it was a whirlwind of helping him craft his pitch to the Modern Love editor and editing his submission. Two months later we learned his essay had been accepted for publication. That led to calls from book agents and he quickly landed a contract with Scribner, a division of Simon and Schuster. It was a dream come true.

Then I got his panicked phone call. His agent wanted to know what his marketing plan was. What, he wanted to know, was she talking about?

This brought us to a rude awakening that all first-time authors experience. It doesn’t matter whether you’re writing your memoirs or the best business book ever. One of the first questions an agent or publisher will ask you is, What is your platform?

And no, they aren’t talking about diving. They’re talking about marketing. And you need to be ready with an answer. These days, marketing a book — even one published by one of the biggest houses in the business — is almost entirely the author’s responsibility. That’s why having a vast network — not just a great idea — is critical. It’s something you should be building now before you start typing your manuscript. It can take two years to build the kind of following publishers want to see.

During a recent thought leadership conference I attended, Noah Schwartzberg, a senior editor at McGraw-Hill Educational stressed this point. “Authors must be able to drive sales through clients, conferences, influencer networks, publicity, and social outreach,” he said, referring to the publisher’s engagements with its authors as “partnerships.”

Here are a few of the questions McGraw-Hill asks aspiring authors to answer in their book proposals:

• Do you give speeches or hold seminars at which your book could be sold?
• If so, how often, to what groups, and what are the audience sizes?
• Do you make regular appearances in print, or on radio or television that might help promote yourself and your book?
• How might your organization contribute to getting the word out about your book?
• Do you have a client list or database of individuals that you could use in direct marketing efforts?
• How many copies would you estimate your clients and your organization might purchase over the first year of sales?

I mean, no pressure or anything. These questions are easier to answer if you’re already well known in your field or backed by a large, global organization like a big consulting firm that can guarantee the publisher it will buy 20,000 copies. But if you’re not, it’s time to start blogging, boosting your LinkedIn following, pursuing speaking engagements, and writing articles for third-party publications.

Many people think it’s writing a book that will make them a star. That’s no longer true. Today, you must pave the road to stardom before you write a book. After that, you can start thinking about writing your proposal.

Even if you get a lucky break like my Modern Love friend, you will still need a network of potential readers larger than your coworkers and extended family. Because as romantic as writing a book sounds, don’t forget: Publishing one is a business.