Which packaging innovation in the publishing industry led to a 35% increase in sales for previously underperforming literary classics in the 1980s?

In the publishing world, cover design is a crucial marketing tool that can make or break a book's success. Throughout literary history, certain packaging innovations have revolutionized how readers interact with and perceive books. This trivia question explores a groundbreaking packaging design innovation that fundamentally changed the publishing industry and influenced how literature is marketed and consumed.

This is a live public trivia poll on AIPolls.Net. Vote and see real-time results.

Embossed lettering on hardcover editions
The introduction of the trade paperback format with artistic cover designs
Glow-in-the-dark book covers for mystery novels
Limited edition cloth-bound covers with ribbon bookmarks