By Amal El-Mohtar and Max Gladstone
Two adversaries, fighting an interminable war across time zones and multiverses, start leaving each other letters via increasingly bizarre and inventive methods. As their relationship grows beyond admiration to love, they face the increasing likelihood of discovery and betrayal.
Verdict: A short SF novel written by two short story experts tells a tale to dive into. Their traitorous correspondence reveals a nightmarish battle between one side changing history whilst the other restores it so each side can be victorious over time. It avoids falling into the trap of over wordy SF by being suffused throughout with understated humour.