Hell's Cartel, By Diarmuid Jeffreys

This impressive book explores how the fourth largest industrial concern in the world switched from energetic capitalism to servicing the Nazi war machine.

A cartel of six German chemical companies formed in 1926, IG Farben (Its full name translates as Community of Interests of Dye-Making Companies) used slave labour to operate a synthetic fuel plant at Auschwitz and made an estimated 10,000 kilos of Zyklon B for gas chambers.

At the Nuremburg trials, the manufacturers of the poison claimed ignorance and were released. The cartel was broken up and its constituent companies, including Bayer, Hoechst, BASF and Agfa, resumed business. Amazing.