The chapter is a journey into the history of electronics. Moving from the discovery of the electromagnetism and its application to the telecommunication through vacuum electron devices, the chapter describes the ideas, the trial-and-errors, and the serendipities that led to the born of the solid-state electronics. The historical tale identifies four main technological phases: point-contact, vacuum, pn junction, and field effect electronics. Eventually, the passage from Germanium to Silicon, from the poly- to the monocrystalline semiconductors and the introduction of the Silicon oxide paved the way to the technology of the microelectronics circuits. For each historical technological phase, the chapter briefly reports the early military and commercial applications.