And that duly happened on Black Monday, October 19, 1987. After several weeks of slipping markets, floods of computer-driven futures orders hit the Chicago markets, overwhelming their systems and driving a steep plunge in futures prices, many all the way to zero, which signalled no bids at all. As futures prices collapsed, the implacable insurance algorithms accelerated the selling. Ms Henriques gives us a gripping, almost minute-by-minute account of the weeks that followed, including the posturings, the denials and the panics, as well as the “web of trust, pluck and improvisation” that pulled the markets through.