and blair effron, al and kathy hubbard.porate funding is provided by stephens, inc. and by pfizer inc. [bright music] - sheila johnson, welcome to "firing line." - thank you so much. this is an honor. - you recently published your memoir. - yes. - "walk through fire: a memoir of love, loss, and triumph." the book starts with you as a 16-year-old girl coming home to the harsh reality that your father, who is a neurosurgeon, your mother, who is an accountant, decided to split up. it was your father's decision. and this, as you write, is a pivotal early moment in your life that shapes you. - absolutely. - [margaret] how? - i had to grow up real fast. i had to take charge of the family. my mother, she just had a complete mental breakdown. and it was a case where my father being one of eight african american neurosurgeons in the country, highly esteemed, my mother, i mean, they were at the top of the social ladder. you know, they were popular. and for him to just walk out was such a shock. and what people don't realize, that bac