I distinctly remember the first time I had pesto -- sublime insouciance, a revelation on my tongue. Then the 1990's happened and everybody served pesto on everything. On bread, on fish, on pasta, on pizza, on your breakfast cereal. It was served year round with old, flavorless basil and too much garlic. It turned me off pesto for a good long time. In fact, I don't think I had eaten pesto in more than a decade.
This passed winter, while perusing my mother-in-law's bookshelves, I discovered Waverly Root's comprehensive guide to the regional foods of Italy, titled, simply enough, 'The Food of Italy.' (Published in 1972 by Vintage Books, a division of Random House. I think it is out of print now, but if you can lay your hands on it, give it a look.) At any rate, in Root's book, I discovered that pesto was invented in Liguria (as was ravioli, so I personally owe those crazy sea-faring Ligurians a big debt of gratitude.) Liguria is the province right around the knee-cap of the peninsula that extends out into the Mediterranean as you can see in this map, and the basil grows thick and lush on the hillsides there. From Root's book: