I have a soft spot for
Emergence by David R. Palmer. It's out of print and not available in e-format to my knowledge. It is about the aftermath of a world war involving nuclear and biological weapons. The only survivors left are a small number of unusually gifted people, some of whom come to believe that they are the next step in human evolution. The story unfolds through a teenager's journal entries as she tries to make sense of the world and just survive.