First of all, there are no indispensable Italian cookbooks. The tradition of Italian cooking is an oral one. I have not seen this book in every Italian home in my twenty years in Italy, nor have I seen brides receiving it regularly as a wedding gift.
But let's take a look inside. Page 7, in enormous bold letters: "eating is a serious matter." Beginning of page 8: "eating is a serious matter in Italy." Who knew? I had no idea, did you? I rather imagined that the Italians had a great dislike and indifference toward the whole matter. Can you say "patronizing?"
It gets worse. Page 929: chicken with tuna. Wrap your brain around that. Does chicken with tuna sound good to you? No, it doesn't. Additional ingredients include anchovies and mayonnaise. Can do without.
Page 290: linguine with Genoese pesto. Dude, where are my pine nuts? No nuts of any sort in the recipe, for that matter. Pshaw!
Throughout the book, you find the instruction "brown the garlic." No you don't. Do not brown garlic. Browning of garlic is what has contributed to the bad name of garlic, which should be rosolato, made golden, not brown.
Poor Italian translations. The category of dried pasta is called paste secche, but the plural of pasta in Italian means pastries. Makes it sound like Homer Simpson is dumpster diving for stale doughnuts. Veal scallops on page 833 are classified under frattaglie, variety meats. Since when is veal a variety meat, either in Italy or America?
And what about the Belgian endive pizza on page 198? Is this a classic of Italian cuisine? It's not a classic of any cuisine, and never will be.