“How am I feeling?” Justice Ruth Bader Ginsburg asked on Saturday, articulating the question on the minds of nervous liberals and many of the 4,000 people who had stood in line for hours to see her interviewed in a cavernous convention center.

“This audience can see,” she said, “that I am alive.” The statement was greeted with thunderous applause. “And I am on my way to being very well,” she added as the room quieted down.

Justice Ginsburg was assisted as she climbed the stairs to the stage, at a book festival sponsored by the Library of Congress. But she was relaxed, alert and cheerful in discussing her life and work.