(Note: This interview first aired in early June.) "Eighty percent of success is showing up." Or so goes the old saying. But what do we really mean by this? And how does "showing up" in life -- or, if you prefer, routinely exhibiting "perseverance" -- relate to things like intellect, talent, drive, discipline, and so on? On this installment of ST, our guest is Dr. Angela Duckworth, a 2013 MacArthur Fellow and professor of psychology at the University of Pennsylvania who has advised the White House, the World Bank, and both NBA and NFL teams. Duckworth gave a much-discussed TED Talk a few years ago, and she has a new book out that's based on it; the book is "Grit: The Power of Passion and Perseverance." Hailed by Publishers Weekly as "an informative and inspiring contribution to the literature of success," this book will speak to parents, teachers, coaches, CEOs, mentors, generals, and various other leaders and professionals. And further, from The Wall Street Journal: "A fascinating tour of the psychological research on success.... A great service of Duckworth's book is her down-to-earth definition of passion. To be gritty, an individual doesn't need to have an obsessive infatuation with a goal. Rather, he needs to show 'consistency over time.' The grittiest people have developed long-term goals and are constantly working toward them." You can access a free, on-demand audio stream of our conversation with Duckworth at this link.