Machine learning enabled by the ever increasing number-crunching power of computers, is a potentially stupendous breakthrough. That is why, by the year 2050, machines will take over much of the work of manufacturing and retail distribution. They can replace many white-collar jobs: routine legal work (such as conveyancing), accountacy, computer coding, medical diagnostics, and even surgery. Many "professionals" will find their hard-earned skills in less demand. In contrast, some skilled service-setor jobs -plumbing and gardening, for instance - require nonroutine interactions with the external world and so will be among the hardest jobs to automate.