Murder on the Orient Express - Agatha Christie

Clever enough but not my favourite - a bit too intellectual and bloodless in structure and style.  Not enough grit.

Let It Bleed - Ian Rankin

An earlier John Rebus novel, I think.  Well-written, but Rebus is not quite as sympathetic a character as he becomes later.  Focus on corruption in high places and links between big organized crime and government figures.

Deadline - Barbara Nadel

Another Ikmen mystery.  Exciting, well-written - her style keeps improving.  Takes place in the Pera Palace hotel with a plot line loosely based on Agatha Christie drawing room mysteries.

ZeroZeroZero - Roberto Saviano

A book by a well-known Italian writer who focuses on the mafia.  This book looks at the cartels in Central and South America, and explores the links between the Italian mafia and these cartels.  Above all, it is a catalogue of the incredible brutality of the cartels' method of operation.
It also explores specifically the world of cocaine, and the obscene profits that the cartels accumulate from this trade.  Saviano also looks at how some of the biggest European, British and American banks are involved in laundering this money for the cartels.  He basically maintains that, especially after the 2009 crash, this cocaine money was what was keeping much of the banking system afloat by providing easy liquidity. 
I couldn't finish it - too repetitive, too depressing.  A great example of how big crime, economic elites and big government all work together.

The Shadowland - Elizabeth Kostova

A novel set in post communist Bulgaria.  The beginning and ending are week, but the main body of the story, which recounts the life of a classical musician under the communist regine, is quite interesting.  Kostova paints an interesting picture of what seems to be a forgotten history.  Bulgaria under communisms underwent something similar to what Stalin perpetrated in Russia - suppression of the educated class, random arrests, labour camps, elimination through gulags of certain sectors of the population.  And then, post communist regime, the rise of apparatchiks in the new corrupt capitalist system. 

The Dawn Watch - Maya Jasanoff

A biography of Joseph Conrad.  The author also sets his novels against the historical events and shifts of the time.  Nice integration of historical perspective and literary themes.  Jasanoff is basically developing the idea that Conrad was ahead of his time in exploring the alienation and rootlessness of modern society, the mechanization of work and the passing of skilled workers and tradesmen, and also the predatory nature of modern capitalism hidden beneath its veneer of social improvement.