This is How You Lose the Time War – Amal El-Mohtar

In the background is a classic time war: Two possible futures are trying to become the only future, and their agents travel through time and possibility to nudge history in ways that will support their future. One future is biological - everything is one intelligent ecosystem - and one future is technological. The best agents of each side (only known as Blue and Red, respectively) begin a secret correspondence.

It starts out as a brutal and super-high-tech game of Spy-vs-Spy. An episode might consist of (I’m making this up) Blue unleashing a world-destroying plague of snakes, only to discover that Red had gotten there first and seeded the world with mongooses - and left a letter encoded in the patterns in one mongoose’s fur. (The encoding has to be bizarre, because it would not end well for either if it were discovered that they were communicating with the enemy.) Then it’s Blue’s turn.

Over time the game changes. The messages become less snarky and more personal. On the average, the agents’ attempted masterstrokes become less brutal and more subtle. The stakes become higher.

The episodic structure of the novel is both a strength and a weakness. Strength, because it gives the authors many chances to be clever - to write short, finely-crafted chapters, each with a clever historical intervention and a clever encoded letter. Weak because the links that tie the episodes into a single story do not convince. The last part of the book, which is meant to tie the episodes into a single narrative, feels pasted-on.

The strengths are real. The episodes are well-crafted, and fun to read. The part that stitches them together could have been better.