This is an interesting book told in epistolary (letter) form. It won the Hugo and Nebula awards for best novella (!). Two agents, Red and Blue, working for different time-traveling agencies, start off as adversaries as they travel up and down multiple timelines to defeat each other’s organizations to prevent them from coming into existence. They are immortal and capable of being any creature they wish to be, mostly killers. Sparring with one another across strands of time, they develop a respect and familiarity with […]