Danielle Steel, who's worth $350 million, says she's been able to pump out 7 books a year because she only sleeps 4 hours a day

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Danielle Steel.

• Danielle Steel is one of the most prolific writers alive, with 179 books to her name.
• To get that much done, she works 20 hours a day, and is lucky if she gets four hours of sleep a night.
• She doesn't believe in "millennial burnout" culture, and has been using the same 1946 Olympia standard typewriter for decades.
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Danielle Steel, the famed author of dozens and dozens of romance novels - including "Star," "Heartbeat," and "Daddy" - writes so much that she barely has time to sleep. If she gets four hours, she considers it a restful night.

The successful writer was recently profiled by Glamour, where she discussed her secret (she's worth $350 million, according to Forbes). She has 20- to 22-hour workdays, but on occasion, she doesn't leave her desk for a full 24 hours. Her process is always the same, decade after decade: sitting down at her desk (which resembles three giant books stacked on top of each other) at 8 am, eating a piece of toast with a decaf iced coffee, and getting to work.

In the profile, 71-year-old Steel railed against "millennial burnout" culture, which she sees as unrealistic. On a recent trip to Amazon's headquarters, she was shocked to see so many perks in a place where work is supposed to be getting done. She told Glamour, "I never expected that quality of life at 25. I had three jobs at the same time, and after work I wrote. Now it's a promise that it's all going to be fun."

And Steel carries that mentality with her wherever she works, either in her home office in San Francisco or in her Paris home. "Dead or alive, rain or shine, I get to my desk and I do my work," Steel told Glamour. She only writes using a 1946 Olympia standard typewriter, and keeps duplicates around for spare parts (she says she can't write on anything else).