Few television shows -- especially canceled ones -- can boast of fan devotion or longevity the way that Star Trek: The Original Series can. Starting in 1966, Star Trek has been part of the zeitgeist for almost 60 years, and thanks to an ever-expanding universe, it can expect to be around for many years to come. The fanbase continues to grow, too. With TOS enjoying new life on Paramount+ and a prequel series with a devoted fan following of its own, more converts are joining old-school fans in their love of Trek. Yet, new fans come with new questions, particularly about The Original Series and its first successor.
Source：https://www.cbr.com/star-trek-tos-tng-biggest-differences/
