Which are These Four Revolutions? The 4th Industrial Revolution is the ‘talk of the town’ at this moment. But which, then, are the previous three? Sentryo is a French company that is pioneering the market for cybersecurity protection for M2M networks and critical industrial systems. As such, it represents the 4th Industrial Revolution par excellence. But the company also knows where to situate the other three: mechanisation replaced agriculture at the end of the 18th century, all because of the invention if the steam engine.