Do you ever feel like you’re really, really busy at work, and then at the end of the day, you look around and realize that you didn’t actually get all that much done? You might have answered some emails and attended some meetings, but you didn’t get to the important, meaningful tasks that you wanted to accomplish.

Cal Newport has noticed this too. “A lot of people think that they are actually focused and getting a lot done,” he says. But “if you’re actually looking at it objectively, you’ll see that’s not at all the case.”

Newport’s the author of Deep Work: Rules for Focused Success in a Distracted World. And he thinks that we need to stop mistaking “shallow work” for “deep work.” Shallow work refers to mundane, day-to-day tasks. Deep work is tougher and involves finding solutions to long-term problems. To use a simpler analogy, Newport says that shallow work is the stuff that keeps you from getting fired; deep work is the stuff that gets you promoted.

And it’s not just random entrepreneurs. Bill Gates has “think weeks,” Carl Jung put himself in a castle, and Charles Darwin was very particular about being left alone to think.

Now, not all of us can ensconce ourselves in castles or buy plane flights to Japan. And our modern world makes focusing pretty tough. According to Newport “even a quick check of an email inbox or a social media website or a cellphone can actually leave a residue for 10-20 minutes that significantly reduces your cognitive capacity.” Open offices too can kill attention. Newport believes they’ve been “a disaster” for productivity.

But it’s not all bad news, you can close yourself off from distractions. You can turn off the internet, power down your phone, retreat into a quiet space… and work (though to be honest, I did check Twitter far too much while writing this article). And if you think that you could stand to spend some more time working on meaningful tasks, Newport has a solution.

“My recommendation is actually that if you work for someone, you actually have a conversation with whoever supervises you, explain to them what shallow work is and what deep work is, and ask them what my ratio should be,” Newport says. “Agree on this, and then come back, and if you’re falling short, say we need to make some changes. And you’d be surprised how malleable some of these workplace cultures are.”