The almost complete (0) AUTOMATION (AUTOMATIC) of equity markets over the past two decades has transformed the daily rhythm of trading floors beyond recognition. Price 1VOLATILE no longer ebbs and flows on a human timescale; orders are placed, matched and cancelled within microseconds, and any firm unable to shave further milliseconds off its 2LATENT finds itself consistently outpaced. Critics argue that the breathless speed of order 3EXECUTE creates conditions in which 4REGULATE struggle even to reconstruct what has happened, let alone to intervene in real time. Sudden withdrawals of 5LIQUID have produced so-called flash crashes, whose 6CASCADE effects can wipe billions off paper valuations in minutes. Market 7ANALYSE remain divided over how serious the risk really is, but even the most enthusiastic defenders of automation now concede that its potential for 8SYSTEM disruption deserves closer study than it has generally received.