I avoid speculation entirely, resisting any urge to try to tackle the many unsolved mysteries by myself. We have to accept there’s a lot we still don’t know. So this book does not rely on guessing. In the moments when my colleagues and I stumbled onto what seemed like big coincidences—seemingly too big, perhaps—or connections we couldn’t explain, we stopped there and discussed them; we didn’t just pick our own theory as to what caused them.
