Excerpt from Give and Take by Adam M. Grant, plus links to reviews, author biography & more

The same pattern emerges in medical school. In a study of more than six hundred medical students in Belgium, the students with the lowest grades had unusually high scores on giver statements like "I love to help others" and "I anticipate the needs of others." The givers went out of their way to help their peers study, sharing what they already knew at the expense of filling gaps in their own knowledge, and it gave their peers a leg up at test time. Salespeople are no different. In a study I led of salespeople in North Carolina, compared with takers and matchers, givers brought in two and a half times less annual sales revenue. They were so concerned about what was best for their customers that they weren't willing to sell aggressively. Across occupations, it appears that givers are just too caring, too trusting, and too willing to sacrifice their own interests for the benefit of others. There's even evidence that compared with takers, on average, givers earn 14 percent less money, have twice the risk of becoming victims of crimes, and are judged as 22 percent less powerful and dominant. So if givers are most likely to land at the bottom of the success ladder, who's at the top—takers or matchers?

Neither. When I took another look at the data, I discovered a surprising pattern: It's the givers again.

As we've seen, the engineers with the lowest productivity are mostly givers. But when we look at the engineers with the highest productivity, the evidence shows that they're givers too. The California engineers with the best objective scores for quantity and quality of results are those who consistently give more to their colleagues than they get. The worst performers and the best performers are givers; takers and matchers are more likely to land in the middle.

This pattern holds up across the board. The Belgian medical students with the lowest grades have unusually high giver scores, but so do the students with the highest grades. Over the course of medical school, being a giver accounts for 11 percent higher grades. Even in sales, I found that the least productive salespeople had 25 percent higher giver scores than average performers—but so did the most productive salespeople. The top performers were givers, and they averaged 50 percent more annual revenue than the takers and matchers. Givers dominate the bottom and the top of the success ladder. Across occupations, if you examine the link between reciprocity styles and success, the givers are more likely to become champs—not only chumps.

Guess which one David Hornik turns out to be?

After Danny Shader signed with the other investor, he had a gnawing feeling. "We just closed a big round. We should be celebrating. Why am I not happier? I was excited about my investor, who's exceptionally bright and talented, but I was missing the opportunity to work with Hornik." Shader wanted to find a way to engage Hornik, but there was a catch. To involve him, Shader and his lead investor would have to sell more of the company, diluting their ownership.

Shader decided it was worth the cost to him personally. Before the financing closed, he invited Hornik to invest in his company. Hornik accepted the offer and made an investment, earning some ownership of the company. He began coming to board meetings, and Shader was impressed with Hornik's ability to push him to consider new directions. "I got to see the other side of him," Shader says. "It had just been overshadowed by how affable he is." Thanks in part to Hornik's advice, Shader's start-up has taken off. It's called PayNearMe, and it enables Americans who don't have a bank account or a credit card to make online purchases with a barcode or a card, and then pay cash for them at participating establishments. Shader landed major partnerships with 7-Eleven and Greyhound to provide these services, and in the first year and a half since launching, PayNearMe has been growing at more than 30 percent per month. As an investor, Hornik has a small share in this growth.

Excerpted from Give and Take by Adam M Grant. Copyright © 2013 by Adam M Grant. Excerpted by permission of Viking. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.