According to PWC US there are eight essential technologies that lead us into the 4th industrial revolution. Historically from a 19th century agrarian economy to three earlier Industrial Revolutions to the Information Age. Our present times are unprecedented and ever-changing - it's "Time for a Change". The PWC eight will soon be ten, which will soon be more because the future always changes.
We welcome all newcomers to the 4IR party as new world-changing products arrive.