Short answers, pulled from the story.
Jack Kilby at Texas Instruments demonstrated the first working integrated circuit on the 12th of September 1958, and won the 2000 Nobel Prize in physics for the invention. About six months later Robert Noyce at Fairchild Semiconductor built the first practical monolithic IC chip, and modern chips descend from Noyce's design rather than Kilby's prototype.
An integrated circuit is a compact assembly of electronic components such as transistors, resistors, and capacitors, fabricated onto a thin, flat piece of semiconductor material. The most common substrate is monocrystalline silicon, though III-V compounds like gallium arsenide are used for specialized applications such as LEDs, lasers, and the highest-speed circuits.
Moore's law is the trend that the number of MOS transistors on an integrated circuit doubles roughly every two years. Gordon Moore first said it would double every year, then revised the figure to every two years in 1975.
NASA's Apollo program was the largest single consumer of integrated circuits between 1961 and 1965, using them in its guidance computer. The Apollo Guidance Computer led and motivated the technology, but it was the Minuteman missile that forced it into mass production for inertial guidance.
Integrated circuits are cheaper because all their components are printed as a single unit by photolithography rather than built one transistor at a time, and packaged ICs use much less material. The average price per integrated circuit fell from $50 in 1962 to $2.33 in 1968.
A semiconductor fabrication facility can cost over twelve billion US dollars to construct. This cost rises over time because of the increasing complexity of new products, a trend known as Rock's law.
The generations are small-scale integration in 1964 with one to ten transistors, medium-scale integration in 1968, large-scale integration in 1971, very-large-scale integration in 1980, and ultra-large-scale integration in 1984 with one million transistors and more. As of 2023, maximum transistor counts have grown beyond 5.3 trillion per chip.