Writing about Monsters and Murderers: SHORT!

I'm reading the remarkable "Walking on the Sea of Clouds" by Gray Rinehart at the moment (review likely posts later today) and his brilliance in character insights has me thinking.

I believe the dictum is "write what you know," which is why Jack London could write about San Francisco and Alaska, and Mark Twain could write about the Mississippi and mining camps. Those are things they did.

BUT: what about people who write about characters who are deeply disturbed?

It's something to consider, isn't it?

Peace be on your household.