Sheryl Sandberg is the chief operating officer at Facebook - but when she lost her husband, suddenly it tipped her world upside down.

She learned about what she calls 'Option B'. 

Well known for her book Lean In, Sandburg has written a new novel with her friend, Professor Adam Grant. It's about resilience, and what to do in times of adversity.

Grant is a psychologist, expert on how we can find motivation and meaning, a professor at the Wharton business school of the University of Pennsylvania, and a New York Times best selling author.

Sandberg approached him for help getting through her husband's death, which turned into them co-authoring the book.

LISTEN ABOVE TO ADAM GRANT'S FULL INTERVIEW WITH MIKE HOSKING