The book I am currently devouring (not literally, of course) is "Winds of the Marble Arch and Other Stories" by Connie Willis. The woman is a genius (plus she sets many of her stories in Denver, which is a nice bonus for me, a Denver native). I just finished "Fire Watch," which from what I understand was one of her earlier works and is fantastic. It's the second story in the collection that deals with the Blitz.
Here's what I like best about so many of her stories: She doesn't throw the speculative element in the reader's face in the first page but instead lets it build. In "Winds of the Marble Arch," the winds themselves don't show up until a few pages in. In "Blued Moon" and "Just Like the Ones I Used To Know," strange things happen but could simply be called coincidence except for a character saying near the end, "Hey, maybe this is what's going on ..."
It has been beaten into my head in the past year -- message boards, critique groups, etc ... -- that the speculative element must appear in the FIRST 13 LINES or you will lose the reader and/or editor who might buy the story. Ms. Willis shows that's not always the case. It seems the 13-line rule is one that can be broken, but to do so, the writer must be willing to pay the price. I suspect the price in this case is the possible loss of readers. Ms. Willis avoids that by writing so compellingly that it's impossible not to keep reading even though there are no aliens, werewolves or spaceships on the first page. But, as I said, Ms. Willis is a genius. I'm not. Still, it's worth experimenting with.