When you’re looking down the barrel of a civilization-erasing event, you have to plan for a world where humanity has lost everything. Canned goods might be nice, but you’d better have brought along a can opener—or know how to make one. What information should we leave survivors? And how do we store it so they can actually make use of it? In recent years, these questions have jumped onto the research agendas of a range of thinkers, from physicists to philosophers to agricultural engineers to librarians, who are considering how to curate and preserve caches of the most useful and important information, tools, and biological samples from today’s world.