Every Italian dish has one rule. And one shortcut nobody forgives.

• Greek settlers named it Neapolis, the “new city,” about 2,500 years ago. Naples still carries the name.
• Neapolitans were once nicknamed “leaf-eaters” for all the greens they ate. When cheap dried pasta arrived, they became the “macaroni-eaters.”
• The earliest printed tomato sauce recipes come from Naples, in a cookbook from 1692. The sauce was meant for meat, not pasta.
• After the war, families sold fried pizza from their doorways, often on credit: eat today, pay in eight days.
• In 2017 UNESCO added the art of the Neapolitan pizza-maker to its list of world heritage.

In the books: Pizza Margherita, pizza fritta, Sunday ragù, pastiera, struffoli

• Under Arab rule, from the 800s, Sicily's kitchens gained sugar, citrus, rice, raisins, pine nuts and saffron. You can taste it in every arancina.
• Palermo says arancina, eastern Sicily says arancino. Italy's language academy says both are right, which settled nothing.
• On December 13, Santa Lucia's day, Palermo traditionally eats no bread and no pasta. Arancine all day instead.
• Every July the city throws a huge festival for Santa Rosalia, its patron saint, with a watermelon pudding on the table.
• Since 2015, nine Arab-Norman buildings in and around Palermo have been a UNESCO World Heritage Site.

In the books: arancine, panelle, caponata, cassata, marzipan fruit

• Tuscan bread is traditionally made without salt. Why? Every Tuscan has a different story, and none of them can be proven.
• The Italian language grew out of the Tuscan spoken in Florence, thanks to writers like Dante.
• In 1716 the Grand Duke drew the official borders of the Chianti wine area, one of the first wine regions defined by law.
• In 1891 a Florentine businessman paid to print his own cookbook after publishers turned it down. It became one of the most important cookbooks in Italian history.
• The story that Catherine de' Medici taught the French to cook? Food historians call it a myth.

In the books: ribollita, peposo, bistecca alla fiorentina, panforte, cantucci

• Between 1880 and 1914, around 4 million Italians came to the United States, most of them from southern Italy and Sicily.
• Every July in Williamsburg, more than a hundred men lift a towering four-ton structure and make it “dance” through the streets: the Giglio feast, brought by immigrants from Nola, near Naples.
• Rainbow cookies aren't from Italy. They were born in Italian-American bakeries in New York.
• “Feast of the Seven Fishes” is an Italian-American name. In Italy, Christmas Eve dinner is simply la Vigilia.
• Sauce or gravy? Families still argue about it.

In the books: Sunday gravy, chicken parm, rainbow cookies, a Seven Fishes Christmas Eve

• An Italian was in Chicago before Chicago was a city: Enrico Tonti, from Gaeta, met the explorer La Salle there in 1682.
• By 1920 Chicago had the third-largest Italian population in the United States.
• When Jane Addams opened Hull House in 1889, Italian families were among its first neighbors.
• Nobody can prove who made the first Italian beef sandwich. It grew out of Chicago's Italian neighborhoods in the 1920s and '30s.
• Locals eat thin, “tavern-style” pizza cut in squares, so it could be eaten off a napkin at the bar.

In the books: Chicago Italian beef, hot giardiniera, tavern-style pizza