The 5th Wave by Rick Yancey

The 5th Wave, now a major motion picture, is a fantasy/apocalyptic novel and although the story focuses on the main character Cassie it is told from differing perspectives. Aliens called 'the Others' have taken over Earth and intend to kill all of humanity. The Others have created waves (get it) of disorder throughout Earth so by the fifth wave all humans are alone for fear of betrayal. Cassie's goal in the first of the trilogy is to find her little brother who is kept at a training camp created by the aliens. Great for fans of Hunger Games or the Divergent series.