How important is a novel’s first sentence?

The first sentence of Mary Robinette Kowal’s ‘Regency fantasy’ novel, ‘Glamour in glass’, disappeared during typesetting, and was only discovered after printing was complete. Rather than collapse in despair, she’s taken some interesting approaches to managing the situation, and thanks to the publicity generated, may well do even better out of it than otherwise!

http://www.maryrobinettekowal.com/journal/new-beginnings-or-what-happened-to-my-novels-first-sentence/

As part of the publicity for it, she’s created a quiz on her website, with the second lines of ten famous books. Visitors can read the quiz and try to pick which novel is which, from multiple-choice answers for each.