Well, clearly it's THE ABILITY TO BE BAKED INTO A LASAGNA.
Behold:
German firm Korefe designed The Real Cookbook (Das Echte und Einzige Kochbuch), a special edition edible cookbook that is made of fresh pasta and can be baked into a lasagne. Gerstenberg Publishing House published this unique cookbook as a special project.
Go look at the pictures!!!!!
(Hey, that reminds me: The Seattle Edible Book Festival is this Saturday.)