This book is the first in a two-partner which I really really wish I’d known before I started it. It’s a great combination of some of Willis' earlier time travel sorts of books along with the weird missed signals theme that carries through a lot of Passages. This book takes us to the London area during the Blitz where three (possibly four) time travelers are doing different historical research topics all of which get a little messed up. The book is rich in history and Willis' excellent writing though it’s a little ... tense for me and especially now that I’ve gotten to the end of it and realize I have to start trolling the libraries to find a way to get the second book or wait for it to be out in paperback. Another great book by Willis, wish I’d had both parts.