I love La Tana! It was founded in 1968 by the parents of Barbara and Diego, which are the ones that currently run the pizzeria/restaurant.
La Tana is located in the heart of Pisa, a street down from Piazza dei Cavaglieri in Via San Frediano.
I would say that if you are planning to have lunch or dinner, you should make a reservation.
Barbara, Diego and their staff are friendly! You are always welcome with a huge smile!
My favorite pizza is mozzarella di buffalo with porcini mushroom. I also love cernia (fish) ravioli with shrimp, asparagus and curry sauce. I also love the carpaccio of tuna atop rugula salad and balsamic sauce. My favorite sweet is their panna cotta with caramel sauce.
Here is the link to their website: La Tana