The City & The City by China Miéville

Book – Tyador Bocity & cityrlú is a detective in Beszel, charged with investigating the murder of an unidentified woman found in one of their slums. His case would be much simpler if he did not believe she was murdered in Ul Quoma, the neighboring city and other half of Beszel, a city which intertwines with his own but whose borders are strictly policed by a shadowy force known as Breach. To unwind the mystery, he must travel across and between these borders, but carefully, because the murderers appear to be extremely powerful – and Breach is always watching.

Miéville’s books always revolve around cities, from the fantastical cities of Bas-Lag to a mystical London, but Beszel and Ul Quoma are perhaps the strangest yet, although there is almost fantastical about them, strictly speaking. This book also features two of the greatest chase scenes I’ve ever read, enabled by the cities’ particularly peculiar geography.