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.