The key takeaway from Bill Gates and Warren Buffett's all-time favorite book

Microsoft co-founder Bill Gates and investor Warren Buffett have been friends for more than 25 years.
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Self-made billionaires and longtime friends Bill Gates and Warren Buffett agree on the best business book ever written: "Business Adventures," by former New Yorker staff writer John Brooks.

The key takeaway from the 1969 classic, a compilation of 12 stories from the world of Wall Street, is as relevant today as it ever was, Gates believes: "John Brooks' work is really about human nature, which is why it has stood the test of time.

"There's an essential human factor in every business endeavor. It doesn't matter if you have a perfect product, production plan and marketing pitch; you'll still need the right people to lead and implement those plans."

Lemonis: The one book every professional should read
Lemonis: The one book every professional should read

It's a lesson that Gates has been reminded of throughout his entrepreneurial career, starting at Microsoft and now at the Bill & Melinda Gates Foundation, he says: "Which people are you going to back? Do their roles fit their abilities? Do they have both the IQ and EQ to succeed?

"Warren is famous for this approach at Berkshire Hathaway, where he buys great businesses run by wonderful managers and then gets out of the way."

They're not the only billionaires who believe in surrounding themselves with other highly successful and motivated people.

"When you look at most big things that get done in the world, they're not done by one person, so you're going to need to build a team," says Facebook co-founder and CEO Mark Zuckerberg. "No one does it alone."

Now check out the 5 best books Bill Gates read in 2016.