"Then you're a fool," he replies without turning, knuckles white on the spine of the book he's handling with careful gentleness. "A reckless and creative mind with a healer's training, experience of soul-eaters, and access to the Grimmauld library, even past access, would be invaluable. But if you won't even declare your reasons for thinking the line of inquiry into a line of healing with the potential to be of such use to so many to be of none whatsoever, then take your damned book and go. It's in the package."