Toshiba's Fujio Masuoka invented Flash sometime in the early 1980s. Most sources today point at the 1984 Integrated Electronics Devices Meeting at which Masuoka discussed and detailed flash (NOR and NAND) for the first time and is credited with the invention of both NOR and NAND Flash.
The first widely known Flash memory device was produced by Intel in 1988. The 256 KB chip came in the size of a shoebox. Of course, Flash is used today in virtually any mass storage solution ranging from chips in our phones, USB sticks, and SSDs. What is most remarkable about the technology is how far Flash has scaled. In the early 2000s, there were discussions when the technology would be replaced, potentially by Ovonics Unified memory (OUM), nanocrystals, MRAM, FeRAM, PFRAM, PCRAM, or Nanotube RAM (NRAM). So far, Flash is still going strong and it will not be replaced anytime soon.