Wikipedia article on Dr. Who. I understood very little about the program, other than I caught a few episodes on cable when I was a kid in the 1980s, and had a crush on Sarah Jane Smith. An article like this would have been very helpful when I was young. It has since become one of my favorite programs.
Also: Doctor Who Scarf, for those of you who particularly like the fourth doctor, Tom Baker. That’s the program I was watching as a kid.