A few months ago I did a bunch of spooky illustrations for a book called Ghost Mysteries: Unraveling the World's Most Mysterious Hauntings. To my surprise, it's now listed on Amazon, although it doesn't come out until August. It usually takes a lot longer for a book to appear--Jack probably won't pop up for months and months.
When I do illustrations for non-fiction books, I get really caught up in the research. This book had so many interesting stories, I may have spent as much time reading articles online as I did drawing the pictures.
Here's a sample.