It was published in 1936. It has sold over 30 million copies. It has been translated into dozens of languages and sits on the shelves of some of the most effective leaders in business, politics, and education.
And almost no one in academia has ever thought to put it in front of a PI.
The book is How to Win Friends and Influence People by Dale Carnegie. And the argument for making it required reading for every principal investigator before they take on their first PhD student is not complicated. Carnegie spent decades studying what makes people feel valued, motivated, and genuinely engaged with their work. That is, word for word, the job description of a research supervisor.
The problem is that almost nobody hired them to do that job. They were hired to publish.
The system rewards the wrong thing
Academic culture has a structural problem that no amount of mentorship training workshops will fix: it rewards narcissistic behavior. The PI who publishes relentlessly, who dominates conference discussions, who builds an empire of citations and grant funding, is the PI who gets promoted, gets tenure, and gets handed a lab full of vulnerable early career researchers to supervise.
Nobody checks whether they know how to develop a person. Nobody asks whether their students leave the lab more confident and capable than when they arrived. The metrics that matter in academia measure output, not the human cost of producing it.
Carnegie understood something that academic hiring committees consistently ignore: the way you treat people is the most important professional skill you have. Everything else, the intelligence, the expertise, the vision, is secondary to whether the people around you feel seen, valued, and genuinely supported.
What genuine interest actually looks like
Carnegie's most foundational principle is this: become genuinely interested in other people.
In a research lab, that means understanding that every person on your team is unique. It means knowing each researcher's specific strengths and finding ways to highlight them rather than flattening everyone into the same model of what a scientist should look like. It means knowing where someone is in their project not because you need a progress update, but because you are actually curious about what they are discovering.
The opposite of genuine interest is not hostility. It is agreement without engagement. A supervisor who agrees with everything a student says is not being supportive. They are avoiding the effort of real engagement. And when criticism eventually comes from outside the lab, from peer reviewers, from committee members, from conference audiences, that same supervisor who agreed with everything will agree with the critics too. The student who thought they had a champion discovers they had a mirror.
This is one of the most damaging patterns in academic supervision, and it is also one of the most invisible, because it wears the costume of niceness.
Don't talk. Show.
Carnegie has a principle about criticism: never criticize, condemn, or complain. In a research environment that requires rigorous critical feedback, this sounds impossible. Science runs on critique. Methodology gets challenged. Data gets questioned. Conclusions get pulled apart.
But Carnegie is not saying never give critical feedback. He is saying never make it personal.
The difference between a PI who develops researchers and one who damages them is not whether they give hard feedback. It is how. The PI who says "this methodology is flawed" is doing their job. The PI who says it in a way that makes the student feel stupid, dispensable, or ashamed is doing something else entirely.
The most effective supervisors teach the how without going personal. Better than that, they show it. They do not lecture about good scientific thinking; they model it. They do not explain how to handle a methodological problem; they work through it alongside you. Don't talk. Show.
Carnegie calls this leading by example. In academia, it is rare enough to be remarkable when you encounter it.
The humility factor
Carnegie has a principle that almost no senior academic ever uses: talk about your own mistakes before criticizing the other person.
The best research supervisor many researchers will ever encounter is the one who, despite being genuinely brilliant, is also genuinely humble. The one who says "I don't know, let's figure it out" rather than performing certainty they don't have. The one whose lab culture makes it safe to not know things, because the supervisor models not knowing things themselves.
This kind of humility is not weakness. It is the most powerful teaching tool available to a mentor. When a PI admits they got something wrong, every student in that room receives permission to get things wrong too, and to say so, and to learn from it rather than hide it.
The labs where researchers flourish are almost always the ones where the PI has enough security to be human in front of their team.
A name is not a small thing
Carnegie writes that a person's name is, to that person, the sweetest and most important sound in any language. It sounds like a small thing. It is not.
When a PI does not remember a student's name, their project, or what they discussed in their last meeting, that student receives a clear message: you are not important enough to remember. In a relationship as consequential as doctoral supervision, where a researcher's entire professional future is intertwined with one person's attention and advocacy, that message lands like a verdict.
Genuine interest requires memory. It requires paying attention. It requires treating each person in your lab as a distinct human being with a distinct story, not a resource allocated to a project.
The professor who never criticized
There is a specific kind of teacher that most researchers encounter once, if they are lucky, who changes how they think about what education can feel like.
The one who was always positive. Who never criticized. Who was genuinely, visibly interested in whether you understood and whether you were growing. Who created a room where everyone became more motivated, more engaged, more willing to try.
This is not manipulation. Carnegie's critics sometimes argue that his principles are cynical, a toolkit for appearing to care without actually caring. But that criticism misunderstands what the book actually teaches. The most effective version of every Carnegie principle requires genuine feeling behind it. You cannot fake sustained interest in another person. People always notice.
The professor who creates a motivated, high-performing class without criticism or pressure is not running a technique. She is running a relationship. Carnegie is simply the person who noticed the pattern and wrote it down.
One principle above all others
If there is a single Carnegie principle that every PI should internalize before supervising their first student, it is this: walk the walk before talking the talk.
Do not tell your students what good science looks like. Show them. Do not explain what intellectual honesty requires. Practice it in front of them. Do not lecture about work-life balance while sending emails at midnight. Do not talk about credit and authorship while quietly migrating their work onto your name.
Researchers watch their supervisors the way children watch their parents, not for what they say, but for what they do when they think nobody is paying particular attention. The lab culture a PI creates is not the one they announce in their welcome email. It is the one they demonstrate every day in small moments.
What to do differently, starting tomorrow
If you are a PI reading this and recognizing something uncomfortable in what has been described, the path forward is not a list of behavioral changes.
It is one thing: stop criticizing and start teaching.
A PI is not a boss. A boss manages outputs. A mentor develops people. The difference between those two roles is not a matter of personality or talent. It is a matter of what you believe your job actually is.
Carnegie understood this in 1936. Academic institutions are still catching up.
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