Tuck Everlasting by Natalie Babbitt (1975)

“If this were Winnie Fosters’s story only, it would be like any other great adventure: you would come to the end, with all resolved, and that would be that. But this is also the story of the Tuck family and therefore, though it has a beginning, and middle, It can never end” 

Tuck Everlasting, Natalie Babbitt, 1975