There's one leadership book Barbara Corcoran loves so much, she buys multiple copies of it at once. Then she gives them out to colleagues, members of her team, or people seeking her advice.

"It's a powerful book that especially gets young people's heads on straight," Corcoran told Entrepreneur. To help rep Amazon's "buy for others" Kindle feature, Corcoran posted on her social channels about it, saying she likes to buy several digital copies and dole them out.

Though How to Win Friends and Influence People by Dale Carnegie was first published in 1936, Corcoran says the content is plenty relevant to today's workplace.

She's not the only one who thinks so. The book has 7,373 reviews on Amazon, with the top reviewer claiming that reading this book changed his life. "I'm being transformed from a socially awkward, timid, and defensive person, to someone that seems collected and confident," another reviewer wrote. It's one of the best-selling business books of all time.

Corcoran particularly likes How to Win Friends and Influence People because it's all about practical advice to build your people skills--or, in business-speak, how to build strong relationships with your team members so you can motivate them to achieve desired results. "There's so much written on the dollars and cents, the left-brain analysis, making the business plan, and such hogwash out there," she told Entrepreneur earlier this year.

How to Win Friends and Influence People is divided into four parts: 1) Fundamental to handling people, 2) Six ways to make people like you, 3) How to win people over to your way of thinking, and 4) How to change people without giving offense or arousing resentment. If you don't feel like reading all 288 pages, there are plenty of summaries to be found that cover the main themes and messages. HubSpot's summary provides a thorough, but not-too-dense read of the book.