Russell Peters answers a viewer's question: "If you hadn't become an internationally known comedian, what other profession do you think you would be in today and why?"

It's the ultimate question: what happens when we die? Is there life after death? Deepak Chopra is a spiritual guru to millions. In his new book, he builds his case for the afterlife. The book is called Life After Death: The Burden of Proof.

Malcolm Gladwell talks about his latest book, "Blink," which suggests our best decisions are often made instantaneously, rather than after long deliberation.

Allan talks to Jimmy and Rosalynn Carter about the Jonathan Demme film "Jimmy Carter Man From the Plains", and also about life after office and the ties that continue to bind them - both in their tireless work as humanitarians and throughout their 61-year marriage. They talk about their passion for advancing world peace, from the 1978 Camp David Accords and the continuing search for peace in the Middle East to the founding of the Carter Center for human rights, which celebrates its 25th anniversary this year. Carter, a Nobel Peace Prize winner, also shares anecdotes about his hands-on involvement with human rights causes, such as building houses for Habitat for Humanity along with Brad Pitt.

Harvard neurologist Dr. Martin Samuels is an expert on the aging brain. He talks about the latest research on how to keep our minds sharp and delay the onset of diseases like Alzheimer's and dementia.

A profile of comedian Russell Peters, shot in 1997.

Nine-eleven. the Asian tsunami, Hurricane Katrina. According to Naomi Klein, these and other crises have been exploited by neo-conservatives to impose radical free-market policies on unwitting citizens. Klein is a journalist, filmmaker and activist, known for her bestseller No Logo. Her provocative new book is called The Shock Doctrine: The Rise of Disaster Capitalism.

Dr. William Molloy is one of Canada's leading researchers on Alzheimer's and gerontology, Dr. Molloy, of McMaster University, discusses the latest findings in slowing the advancement of Alzheimer's.

Psychiatrist and psychoanalyst, Dr. Norman Doidge talks about an astonishing new science called neuroplasticity, which is overthrowing the centuries-old notion that the human brain is immutable. His new book, "The Brain That Changes Itself: Stories Of Personal Triumph From The Frontiers Of Brain Science" will permanently alter the way we look at our brains, human nature, and human potential.

Allan Gregg talks to Dr. Oliver Sacks, the world-renowned neurologist made famous by the movie "Awakenings", and who has released a new book "The Island of the Colorblind."