The adventures in time and space of the Doctor, a Time Lord who changes appearance and personality by regenerating when near death, and is joined by companions in battles against aliens and other megalomaniacs.
Start with the first story: "An Unearthly Child" (available on DVD), and go from there. Mind you, not every story/episode from the original series does not exist. Sadly, this does interrupt a fan's collection, however the audio soundtracks for every story are available on CD or Audio Download.