Annihilation - Jeff VanderMeer

This is a deeply unsettling novel, that follows the 12th expedition sent in to explore the mysterious 'Area X'. We know nothing about the expedition members except their professions, even names are considered to be a luxury here. Our narrator is the biologist, she has personal links to an earlier expedition, and is the only group member who reveals anything about herself.
This expedition has been told that they are the 12th to enter this unexplained area, and they know that each of the preceding groups suffered terrible fates, often turning on each other. It quickly becomes clear that this expedition will be no exception as one member, the anthropologist, is found dead in deeply unusual circumstances.
It is never clear how much of the biologist's experiences can be trusted, how much is due to here hypnotised state, and how much is simply hallucination. The story ramps up the sense of unreality and horror and by the end we are left with no clear conclusions either about the nature of Area X of the motivation of the sinister Southern Reach, luckily the second and third instalments of this trilogy are due to be published later on this year so we won't have to wait too long to find out the truth.