In 1931, Winston Churchill found himself more or less exiled from political life. In the previous years he had found himself vehemently fighting members of his own party over a number of issues and when a new government was formed, Churchill was not invited. He was viewed as out of date and out of touch by his fellow politicians and so began a period now known as his “wilderness years.”

An ordinary politician would have been powerless when voted out of office or driven to the fringes by political enemies. Not Churchill. Because he held onto something even more valuable than office—he had a platform.

Most people are unaware that Churchill made his living as a writer, publishing some ten million words in his lifetime in hundreds of publications and published works. In fact, it was his enormous worldwide readership that Churchill cultivated through books, newspaper columns, and radio appearances that allowed him to survive the periods in which he did not have the ability to directly shape policy. Instead, he was able to reach directly to the people about the rising threat of world war, not just in Britain but worldwide, including in America. During his infamous time in the so-called political wilderness between 1931 and 1939, Churchill published 11 volumes and more than 400 articles, and delivered more than 350 speeches. His enormous platform—based on his editorial contacts, his extraordinary gift with words, and his relentless energy—allowed him not only to be relevant but also to guide policy and opinion across the globe until he was eventually brought back in to save Britain and eventually and in many ways, the world.

For any kind of leader, creator or entrepreneur, this kind of platform is essential. Because it is the ultimate insurance policy and the most durable form of influence and power.

Michael Hyatt, former CEO of Thomas Nelson Publishers, writes that, “In the old days, you could stand on a small hill or a wooden stage to be heard. That was your platform.” In the literal sense, that’s a platform. This was the tool and the approach you used so that you and your message could reach people. Today, people think of a “platform” a bit differently. Many see it as how many social media followers you have, or the ratings of a television show. I would argue that this definition is almost equally simplistic.

In my definition, a platform is the combination of the tools, relationships, access, and audience that you have to bear on spreading your ideas—not just once, but over the course of a career. So a platform is your social media and the stage you stand on, but it also includes your friends, your body of work, the community your work exists in, the media outlets and influencers who appreciate what you do, your e-mail list, the trust you’ve built, your sources of income, and countless other assets. A platform is what you cultivate and grow not just through your work, but for creative work, whatever it may be.

The question, then, is: How do we build an audience of this kind? How do we develop something that supports us perennially throughout our career?

In 2008, I came to the realization that while I would one day like to publish a book, unless things changed, I would have no way of actually telling readers about my book. I decided I would build an e-mail list. But what about? I wasn’t important or interesting enough for people to just sign up based on my name alone. So I came up with an idea: What if I gave monthly book recommendations? (The thinking being that one day I might recommended one of my own books to this list.) Once a month for four years I sent this list out, and as a result it grew from ninety original sign-ups to the five thousand people to whom I announced my first book. By the time my next book came out two years later, the list was at more than thirty thousand, and today it’s at more than eighty thousand.

With the release of my latest book, Perennial Seller, I didn’t need to do as much marketing or beg to be on every podcast. The vast majority of people I wanted to reach with the book were already signed up for my list, they were already in contact with me. I just had to reach out and say: Hey, I need your support! (and in the future, if I were to ever be dropped by my publisher or driven to some sort of authorial wilderness, I would always have this support to fall back on).

This is the reason that if I could give a prospective creative only one piece of advice about platform, it would be this: Build a list. Specifically, an e-mail list. Why? Imagine that, for reasons entirely outside of your control, there was a media and industry blackout of your work. Imagine that, due to some controversy or sudden change in public tastes, you were suddenly persona non grata. Imagine if no publisher, no crowdfunding platform, no retailer, no distributors, and no investors would touch what you’ve made.

Think about a band like Iron Maiden—radio hasn’t played their kind of music since the mid 80’s. MTV hasn’t played their kind of videos in almost as long. But in that time they’ve put out a dozen albums which have sold millions of copies. How? Because their relationship was directly with their audience. They had a platform. They have an enormous email list.

There is a theory about the entertainment business put forward by Kevin Kelly, the founder of Wired magazine. He calls it 1,000 True Fans: “A creator, such as an artist, musician, photographer, craftsperson, performer, animator, designer, videomaker, or author—in other words, anyone producing works of art—needs to acquire only 1,000 True Fans to make a living.”

With one thousand true fans—people “who will purchase anything and everything you produce”—you’re more or less guaranteed a livable income provided that you continue to produce consistently great work. It’s a small empire and one that must be kept up, but an empire nonetheless. Iron Maiden has more than 1,000 fans, just as Churchill did, and it’s what allowed them to reach so many people.

After his successful launch of his book Choose Yourself, my client James Altucher completely embraced self-publishing and all it entailed. He built a podcast that he distributes directly through his e-mail list. He then created an exclusive, high-ticket newsletter that gives financial advice through e-mail. He created a members-only book club. He wrote several more books, selling many of them directly through his website and thus amassing not only hundreds of thousands of e-mail addresses, but physical mailing lists and payment information for his fans as well. It’s now a huge platform that, by his estimation, grosses more than $20 million a year in revenue.

As creators, to do our work without a platform is to be at the mercy of other people’s permission. As business people, to not have a platform means we are dependent on having a certain job, or backing. Someone else must fund us, someone else must give us the green light, someone else must choose to let us make our work. To a creative person, that is death. It’s not a career, it’s a dependency. Having an audience that we own? That we’re bound together with like hand and fist? That is life. Yet as I’ve said before: This does not just happen. It must be built.

So don’t wait. Build your platform now. Build it before your first project, before your first great perennial seller comes out, so that you have a better chance of actually turning it into one. Build it now so that you might create multiple works like that. Build it so you can have a career—so you can be more than just a guy or gal with a book or movie or app. Because you’re more than that. You’re an entrepreneur, an author, a filmmaker, a journalist. You’re a mogul.

This won’t just happen. You have to make it happen.

Hidden from view for the vast majority of public is a little page that explains the complicated methodology behind the famous New York Times Bestseller list. And buried mid-way through that explanation is an unusual phrase. It says, with matter-of-factness, “among the categories not actively tracked at this time” by the editors at the Times are so-called “perennial sellers.”

To people not in the industry, this is a strange phrase. Perennial sellers? Like books about flowers? What does that mean?

In fact, it’s an industry term for perhaps the most important type of book in publishing, one that some estimate is responsible for the vast majority of the revenue for the $70 billion dollar book industry: the titles published long ago that keep selling without fanfare and without attention. That’s what a perennial seller is: a product that keeps reaching new customers week in and week out, year in and year out.

Nor is publishing the only industry that has this trend or this concept. In 2015, “catalog albums”—albums 18 months or older—outsold all new releases. In Hollywood, it’s the “library” that funds the massive budgets of the blockbusters that come out each year (and keep the companies in business when the majority of these movies inevitably lose money).

Perennial sellers are books like What To Expect When You’re Expecting, Good to Great, The Great Gatsby, movies like “The Shawshank Redemption” or “A Christmas Story,” or songs like “Happy Birthday” or “Candle In The Wind.” It’s products like Red Wing’s 1907 Work Boot (which confusingly only dates back to the 1950s) or restaurants like The Original Pantry, which has been open every single day since 1924.

If you think I am overstating the economic impact of perennial sellers in these billion dollar industries, a few examples are illustrative: The late Harper Lee’s will contained a clause which stated that her estate would no longer consent to mass market paperback editions of To Kill A Mockingbird. This edition was so profitable and such a reliable sales engine for Hachette that sent executives panicking about how they might replace it. Or look at this list of the bestselling rock albums of 2015. Notice something? Of the 20 albums, a full 10 of them are more than a year old—in fact, the average age of the album on the list is 10 years (and the oldest is 40). Or take the estate of Michael Jackson, which was valuable less because of his music but because of the music of other artists. His empire of copyrights and music libraries, which he bought up over the course of his career, generates hundreds of millions of dollars in revenue to this day. Most famously, he bought the rights to the Beatles catalog—partly because he believed it was worth more than the Beatles did (a decision they came to regret).

Jay Z once rapped, “Own your masters, slaves!” Why? Because that’s where the money is in the music business. As I tell authors and creatives, forget creating a bestseller. Create a perennial seller. Because perennial sellers are the revenue engines of the creative industry. They are like gold or land—they go up year after year—they pay like annuities.

But the paradox of this economic fact is that almost no one in the music, movie or publishing industry focuses on this. As Seth Godin once observed, “Book publishers make more than 90% of their profit from books they published more than six months ago. And yet they put 2% of their effort into promoting and selling those books. Editors, agents, salespeople all focus on what’s new, instead of what works.”

They seem to think that perennial sellers are created by accident. Or that because they are dependable, they’re boring. So agents and execs chase the next big hit, the next big star and try to get lucky. They chase a dragon, an addiction that, in the end, bankrupts most of them.

As mind-bendingly stupid as this is, it’s also good news.

Because it means that if you ignore that noise and create something that lasts, you can write your own ticket. It also means there are all sorts of lessons to be learned from the classics that the so-called experts have deliberately declined to learn.

With my own books, I try to follow Jeff Bezos’s advice: Focus on the things that don’t change. As the founder of Amazon, he knows a thing or two about what customers really want. It’s not what’s new. It’s what works. What’s best. What fills their needs. What’s cheap and accessible. And this was true 100 years ago and it will be true in a 100 years.

The fact that my clients have sold north of 10 million books isn’t what I’m proud of. It’s that they continue to sell hundreds of thousands of copies each year. That several of the books I’ve written have debuted on bestseller lists is great—I love having a framed copy of the Wall Street Journal on the wall in my office. That they aren’t on the list this week or that week? I don’t care. What really matters to me is that the books have continued to sell. (My book The Obstacle is the Way will sell more copies in 2017 than it did in 2016, and sold more in 2016 than it did in 2015 and 2014). That’s what being perennial is about.

This wasn’t easy to do, but I have done it. Not once, but several times now. And so have thousands of other creators, building their careers around timeless principles and avoiding the toxic advice and fads of their industries.

In the next couple weeks and months you’re going to see me writing and talking about this concept a lot so I wanted to take a minute first to define my terms. I also wanted to explain why it matters, even if you’re not an author or a musician or a movie producer.

No one sits down to make something hoping it will disappear. No, the whole point is to stand the test of time. And that’s true whether you’re building a small side hustle or opening a coffee shop or putting on a play. The reason you get up each morning and throw yourself into it—in a way that you would never throw yourself into a memo at the office or another conference call—is because you believe in what you’re doing and you know that there is something special about it.

Success then isn’t something you’re after for a month or two. You want to be evergreen. To sell for decades. To be classic. To make the backlist. To be a perennial seller.

Because that’s where the impact is, in reaching people, and lasting.

You can read all about this in my book Perennial Seller: The Art of Making and Marketing Work that Lasts which is officially out now. James Altucher has said it’s my best book yet and Michael Rapino, the CEO and president of Live Nation, says it’s a “formula for becoming a classic and legendary.” I hope you enjoy it.