This is How You Lose the Time War

Pick it up: If you;'re looking for sci-fi with an element of romance, but told in an unconventional style.

This is a mind bending, ingenious, entertaining read. This is the story of Red and Blue, two rival agents in a war that spans across time and reality, and that seeks to shape the future. Red works for the Agency, a technologically advanced, structured organization, while Blue serves the Garden, a faction focused on organic and natural evolution. Despite their opposing allegiances, they begin to exchange letters, initially as taunts and boasts left for one another across the battlefields of time. 

The story unfolds through this correspondence between Red and Blue, who never share time, and whose letters must take ingenious shapes and forms in order for them to be a secret and hidden from the eyes of their superiors. Because what they are doing amounts to treason. They both grapple with their identities as agents in a war that demands unfailing loyalty. But as their connection deepens with the letters, they start to question their allegiances and their roles in the conflict. Their admiration for each other's cunning and intellect gradually evolves into love.

The novella is a collaboration between Amal El-Mohtar who wrote Blue and Max Gladstone who wrote the part of Red. The writing is beautiful and while it can be tricky to follow the language of their time travel, you slowly settle in and get comfortable.

The novel has won numerous awards, including the Hugo Award for Best Novella, the Nebula Award for Best Novella, and the Locus Award for Best Novella.