This Is How You Lose the Time War by Max Gladstone and Amal El-Mohtar is a science fiction fantasy novella told through letters exchanged between two rival time-traveling agents, Red and Blue, who work for opposing factions in a temporal war. What starts as battlefield taunts evolves into a secret, deep love across time and space. Their correspondence challenges their loyalty as they navigate danger, shifting histories, and a war that spans multiple timelines. The novel is acclaimed for its lyrical prose and exploration of love, identity, and the paradoxes of time travel.