Series, Serials and Cereal

I used to avidly read series of novels when I was a child. Biggles, the Chalet School, Barnabas Collins (though I never saw the TV series), and more. At first I didn't care what order I read the stories in; I just picked them by the title or the picture on the cover, knowing I was bound to enjoy the story too. But I gradually learned how the tales fit together; Chalet girls grew older, got married and had daughters of their own; Barnabas Collins? --- I never quite figured him out; and Biggles...