"This one feels important. I'll have to look through it to be sure," Claudia says, giving a dismissive shrug. "My hunches aren't always that reliable, but I get these feelings sometimes. Like when my brother was about to do something really stupid and dangerous."

She has a vague memory of him trying something and that's how she lost him for years.

"One thing I've learned, though, is that sometimes the strangest things end up being relevant. Like Rheticus's poetry."