From primitive observations of neural phenomena in frogs to the sophisticated digital instrumentation of the present day, this chapter traces the historical evolution of electroencephalogram (EEG) technology. Different sections explore specific milestones, spanning the foundational era of analog EEG instrumentation to the transformative shift to digital EEG. This progression unlocks ever-new possibilities for recording, analyzing, and interpreting the brain’s electrical activity. Advancements in electrode and amplifier technology, coupled with efforts to enhance portability and user-friendliness, drive the development of wearable EEG systems, expanding their utility beyond traditional laboratory settings. Brain–computer interface systems represent a significant advancement, enabling users to translate their thoughts into actions and control external devices with neural signals. Lastly, the exploration of brain-to-brain interfaces brings us to the realm of collective consciousness, suggesting fascinating possibilities for shared cognition and communication.