Ellis Peters's historical detail is very accurate and very minute, and therefore is not only interesting to read but good for an actor to acquire a sense of the period. And the other thing I think is that an actor lives in the land of imagination.
I mean, I spent 30 years in the world of physical perfection, right? I've known most of the world's most perfect physical specimens over the course of the last 30 years.
Whereas you have someone like Houdini, who works really, really hard to get really, really famous, and then has actual intellectual ideas that he puts into the culture that stay there.