In recognition of Warren Buffett’s ninetieth birthday, an article by McKinsey  & Company takes a look back at the “steady genius” of one of America’s most influential and wealthy business leaders, describing him as “a study in the logic and discipline of understanding future value.”

According to the article, Buffett and his firm Berkshire Hathaway have “earned millions of dollars for investors over several decades. But very few of Buffett’s investment decisions have been reactionary; instead, his choices and communications have been—and remain—grounded in logic and value.”

The article outlines some of Buffett’s strategies, including his focus on businesses that “have steady cash flows and will generate high returns and low risk” and on strong management teams. It cites comments from Peter Kunhardt, director of the HBO documentary Becoming Warren Buffett, who said in a 2017 interview that Buffett understands that “you don’t have to trade things all the time; you can sit on things, too. You don’t have to make many decisions in life to make a lot of money.”

While Buffett has clearly made some mistakes, the article says many of his theories “continue to win the day” and that the veteran investor has shown the “value in consistency, caution and patience and in simply trusting the math—in good times and bad.”