The discovery of fire has generally been considered as the first and most significant discovery of mankind. Millenia and four industrial revolutions later, humanity has forged ahead and shown no signs of slowing down the scientific and technical progress. The first industrial revolution was marked by mechanization using steam and water power. Progress was slow, and the implementation of new technologies took more than half a century. The second industrial revolution, also known as the technological revolution, was made possible with the railroad and communication networks which allowed faster transfer of people and ideas. The discovery of electricity allowed for factory electrification and the invention of modern production lines, also known as mass production. The third industrial revolution occurred at the end of the second world war. Accompanied by the invention of transistors and microprocessors, it was called the digital revolution. The extensive use of computer and communication technologies led to globalization and the information age, paving the way towards the fourth industrial revolution. Both the second and third revolutions caused a temporary surge in unemployment as many human workers were replaced by machines.
The fourth industrial revolution or Industry 4.0 (I4), as it was rechristened at the 2011 Hannover Trade Fair in Germany, describes the trend towards automation and mass customization in manufacturing technologies and processes, which include cyber-physical systems, the internet of things, industrial internet of things, cloud computing, cognitive computing, and artificial intelligence. The industrial internet of things refers to interconnected sensors, instruments, and other devices networked together with computers' industrial applications, including manufacturing and energy management. This connectivity allows for data collection, exchange, and analysis, facilitating improvements in productivity and efficiency as well as other economic benefits.