I’ve long puzzled over differing interest in history and the future, in both fiction and non-fiction. And I’ve finally collected some numbers.

Amazon.com says it has 37 million books on offer. Here are the fraction of those books it says are in these named categories:

Note that Amazon has no “future studies” category, so I listed the two future-themed categories I found. Here are the fraction of books associated with related keyword phrases:

Why the far larger interest in real history, relative to all the other combinations of future/history and real/fictional? It can’t just be a simple history vs. future effect, nor a real vs fiction effect – it is some sort of combination effect.