AAUGH Blog reader Fred Dingledy put some research muscle into the question of the odd title of the German Peanuts book Love is a Book with Seven Seals:
it looks as if “ein Buch mit sieben Sigeln” is a German expression referring to someone or something that can’t be understood (i.e., can’t be read). The expression is apparently taken from Revelations 5:1-5, which refers to a scroll with seven seals that no one could open.
This aphorism also appears on the interior of the German edition, alongside the image they used on the cover. This concept that “Love is a thing that cannot be understood” is quite a contrast to the one by that illustration in the U.S. edition of the book, “Love is liking ideas”.