"Speculative" fiction is a term that is often used to encompass all kinds of scifi, fantasy, horror, and all of the various blends in between. Sometimes when stories live in the intersection of these -- fantasy and horror, horror and scifi, etc, etc -- they do even better than the purists because they cross over in their appeal, and sometimes they end up too niche to appeal to either audience.
         So take that risk, combine it with a story set during World War II -- so historical fiction to boot -- and throw in a bunch of famous scientists and mathematicians, like Einstein, Godel, and Oppenheimer, and you have the foundation that makes up The Einstein Prophecy, by Robert Masello.
         I stumbled across the book without knowing anything about the author or really, the premise beyond the little blurb on Amazon, but I have to say, I was pleasantly surprised with how it all played out. I didn't really see a whole lot of prophecy in The Einstein Prophecy, but the title does do a good job of capturing the combination of science and fantasy that is at the core of the story-- a collision of demons and atomic bombs, and of ancient history and breakthrough scientific discoveries.
         Lucas Athan is an art historian tasked with recovering stolen art from the Nazis during the latter days of World War II. Yep, that sounds a lot like the movie Monuments Men. Except that Lucas is sent specifically after a unique artifact from Egypt, one that happens to bring a lot of bad luck with it -- bad luck that leads to Lucas losing an eye and being sent home. Yes, perhaps you're thinking that this sounds a lot like Raiders of the Lost Ark. Except that Lucas is paired with scientist Robert Delaney, a pioneer of carbon dating, and Egyptologist Simone Rashid to figure out what it is about this artifact that made the Nazis want it so badly. And this investigation takes place at Princeton University, where Lucas is a professor -- and where Einstein is in residence, concealing the help he is providing to Oppenheimer on his own quest to beat the Nazis to the atomic bomb. Lucas's work and Einstein's collide in unexpected ways, leading to plenty of action, well-told.
         I had one logic issue with the way the story proceeded, which I can't really get into without giving away the ending, but it centers on the cat (not Schrodinger's cat, but Einstein's), and the ultimate motives of the villain in this story, but by the time I reached the end of the book, I was still a satisfied reader -- enough that I would give this story at least 4 stars, if not more.
         Now, I will say that when you're dealing with history, and especially a story that takes some liberties with history, there's always the risk that you're going to upset people who know a lot about a subject, like how Einstein spent the years of World War II, for example. And certainly, some of the criticism of The Einstein Prophecy comes from people who objected to the liberties that Masello took with what actually happened.
         But for my part, I think a book that takes on presenting an alternate version of past events should be judged not by the people who know what actually happened but by those who don't. Dan Brown's The DaVinci Code is a good example. After reading the story and having all of the symbology described in art that is only a Google search away, I felt compelled to look up those works of art to see if those symbols were actually there. The alternative events described in the book were enough to spark my curiosity into what actually did happen.
         The Einstein Prophecy does that as well -- the events that make up the plot of the book were believable enough to someone who did not really know how Einstein spent the years of World War II (that would be me), and yet intriguing enough to make me wonder how much was actually true vs. liberties taken by the author. And even after the author took the time to explain where he diverged from history (which I appreciated), I'm still curious enough about those years and about the quirks of famous characters described in the story to maybe do a little more research into history than I would have if I'd never picked up the book.
         And that is exactly the kind of reaction that someone taking on alternative history, fantasy, and science all at once should hope for.