This document discusses the history of industrial revolutions and how 3D printing fits within the context of the current fourth industrial revolution. It outlines key inventions from the first three industrial revolutions including the steam engine, airplane, and computer. The fourth industrial revolution is characterized by unprecedented developments in areas like genetics, nanotechnology, and artificial intelligence. 3D printing is described as a technology that builds 3D objects from digital models using materials like plastic that harden after being heated and deposited layer by layer.