Q is a fictional character, as well as the name of a race, in Star Trek, appearing in the Next Generation, Deep Space Nine, Voyager, Lower Decks, and Picard series and in related media. The most familiar Q is portrayed by John de Lancie. He is an extra-dimensional being of unknown origin who possesses immeasurable power over time, space, the laws of physics, and reality itself, being capable of altering it to his whim. Despite his vast knowledge and experience spanning untold eons, he is not above practical jokes for his own personal amusement, for a Machiavellian or manipulative purpose, or to prove a point. He is said to be almost completely omnipotent and he is continually evasive regarding his true motivations. The name "Q" applies to the names of the individuals portrayed (all male and female characters refer to each other as "Q"); it also applies to the name of their race and to the "Q Continuum" itself – an alternate dimension accessible to only the Q and their "invited" guests. The true nature of the realm is said to be beyond the comprehension of "lesser beings" such as humans, therefore it is shown to humans only in ways they can understand; e.g., a run-down gas station in the 'middle of nowhere'. Beginning with the pilot episode "Encounter at Farpoint" of The Next Generation, Q became a recurring character, with pronounced comedic and dramatic chemistry with Jean-Luc Picard. He serves as a major antagonist throughout The Next Generation, playing a pivotal role in both the first and final episodes. Q is initially presented as a cosmic force judging humanity to see if it is becoming a threat to the universe, but as the series progresses, his role morphs more into one of a teacher to Picard and the human race generally – albeit often in seemingly destructive or disruptive ways, subject to his own amusement. Other times, notably during "Deja Q" and Voyager, Q appears to the crew seeking assistance. Gene Roddenberry chose the letter "Q" in honor of his friend Janet Quarton. Source: Wikipedia (en)