Do you have a mentor? You know, someone who you can ask for advice on occasion, someone that might be able to help you navigate the political puzzles of corporate life? Today, more than ever before, companies are appointing mentors for junior staff and who’s to say that’s a bad idea?

Except for one little problem. Every company I know is focused on attracting and developing world-class talent, yet consistently falls short. What’s more, helping talented young hires succeed is more difficult today than in years gone by, in part because those so-called “mentees” don’t just want a mentor, they want something more. They want to see their careers accelerate right from the start, and they’re not interested in an occasional check-in with a grey beard.

Well, what if I told you that there is a breed of boss out there who goes far beyond what any traditional mentor might do? I call them “superbosses” — men and women who exceed our traditional concepts of what a mentor is or can be to help others accomplish more than they ever thought possible. Over time, many superboss proteges go on to dominate entire industries, taking up top jobs and creating new businesses.

What makes them super?

Most business mentors don’t maintain deep, intense relationships with their younger, less experienced mentees. They may meet occasionally, dispense a few helpful tips, or help a mentee make helpful personal contacts, but that’s about it.

Superbosses are what I’d call “activist bosses”. They are consistently present to guide and teach their proteges, and they behave in certain ways that help employees reach great heights. Would your typical corporate mentor check in with you at 01:00 to see how your big project is going? A superboss would. Would your typical corporate mentor give you the exact feedback you need to hear, when you need to hear it? A superboss would. Would your typical mentor sit 10 feet away from you, taking time to comment on the nuances of your work so that you learned at the feet of a master? A superboss would. It is this intense, sustained effort that allows superbosses to play such a big part in the success of others.

Superbosses create value within organizations by making others feel valued and empowered — the path to extraordinary success is founded on making others successful. Survival depends on this very fact. No leader can survive and prosper without regenerating the talent pool.

Although superbosses are very different in many personal ways, their motivation as bosses can be categorized into three distinct types: nurturers, iconoclasts, and glorious egoists.

The nurturer

Let’s start with the nurturer, who creates something akin to a master-apprentice relationship with her team members. I’m talking about workplace relationships that are more sustained, all-encompassing, intense and intimate than the best traditional corporate mentorships.

Although the boundaries of these relationships may be unspoken or undefined, nurturers take much deeper personal responsibility for the growth and development of employees than conventionally good bosses do, and the recipients of this attention in turn end up with far more instruction and feedback than their counterparts at other organizations. Nurturers include people like Bill Walsh (former head coach of American football’s San Francisco 49ers), legendary cosmetic mogul Mary Kay Ash, and the man who almost single-handedly created the-fast casual restaurant industry, Norman Brinker.

The iconoclast

In contrast, iconoclasts don’t consciously develop talent. Their goal is not to teach or inspire. Their passion is their work. Miles Davis was a prime example of an iconoclast. Because Davis was so fixated on the vision of his own music, his fellow musicians learned intuitively and organically from Davis’s passion. The lessons weren’t conscious or methodical.

Such superbosses are usually seen as creative geniuses, and include filmmaker George Lucas, fashion icon Ralph Lauren, and Lorne Michaels, the creator Saturday Night Live, an American TV show. Ambitious colleagues are drawn to these types, eager to absorb creative energy and expression. Iconoclasts welcome new collaborations to keep their own art fresh and relevant. It’s a very symbiotic relationship.

The glorious egoist

Finally, there’s the glorious egoist, the superboss who is more attuned to winning rather than developing others. They must win, no matter what. Many times, glorious egoists will be known to be harsh critics, merciless in their feedback and even unpleasant. Yet, they produce results. They win. And they spawn talent along the way.

This is because glorious egoists understand they need the absolute best teams made of the best people to win. While hungry for personal fame and glory, they still know their success is built on the success of those around them. The glorious egoist is both feared and respected, and people know that working for one will put their careers on the fast track. Glorious egoists include Oracle CEO Larry Ellison, advertising guru Jay Chiat and former financier Michael Milken.

Out-of-the-box thinking

In sum, these three different types of superbosses don’t fall neatly into our traditional views of mentorship. And that’s the point. Sticking to outdated and potentially limited thinking when it comes to developing talent won’t cut it any more.

For companies, nothing short of a completely fresh look at how they develop talent is called for. For executives, it’s time for a new assessment of what it takes to help other people accomplish more than they ever thought possible. And for all those people looking to work for a boss who can truly turbocharge your career, rest assured that some bosses have figured out how to do exactly that. We call them superbosses.

Sydney Finkelstein is the Steven Roth Professor of Management and Director of the Leadership Center at the Tuck School of Business at Dartmouth College. His new book is Superbosses: How Exceptional Leaders Manage the Flow of Talent (Portfolio/Penguin, 2016).