A psychologist, a biologist, a surveyor, and an anthropologist walk into Area X. This sounds like a "walk into a bar" joke. Okay then, the punch line: not all of them will make it out. Bad joke, but a fairly good read. Area X has been cordoned off by an unexplained barrier for the last three decades. The four women mentioned above comprise the 12th expedition into this place which is no longer inhabited by people, and which has seemingly returned to a state of nature. We quickly realize that some things are very unnatural here, without a conceived explanation, and unlike nature cannot be trusted as genuine. This could also be said for the expedition itself, and the reason they were sent. 
 The book reads as a journal written by one of the women. It lends realness to the story. I'm cryptic with explaining the plot because that's kind of the way I feel about the book. By the final page, there are really more questions left than answers given. Annihilation is not a stand-alone book. It is the first of the "Southern Reach Trilogy", and I suppose like most series, the first is meant to leave the reader wanting more. I will move onto the next book, Authority, because the first one left me with just enough desire to do so. Some parts were intensely scary, while others were plodding. By the end we meet what at least partly defines the unexplained in Area X. That was good, but it also left me asking if I'll care for the final answers.