Step 1: Briefly describe the origins of printing. Early printing, predating Gutenberg's press, began in China using woodblock methods.
Step 2: Determine the oldest dated instance. The earliest known complete, dated printed book is a copy of the Diamond Sutra, a Buddhist text.
Step 3: Add details about the book. This copy, discovered in a sealed cave in Dunhuang, China, in the early 20th century, is a woodblock-printed scroll, roughly 16 feet long. It features a colophon indicating production in "the 9th year of Xiantong of the Tang Dynasty," which equates to May 11, 868 CE. The Biblia Pauperum is a European block-book from the 15th century.