Charlie, who lives in America, and Carlitos, his cousin who lives in Mexico, decide to write each other about their daily lives. They have never met. At first, they seem to be very different from each other: Charlie lives in a city with skyscrapers whereas Carlitos resides on a farm where they grow maiz. The Mexican rides his bike to school whereas the city dweller rides to school on a subway. One plays futbol at recess and the other loves basketball. But then slowly, the two discover activities they have in common: going shopping for food with their mothers, playing after school, enjoying festive occasions, and participating in special holidays. Then magically, they both come up with the same idea at the same time!

Dear Primo: A Letter to My Cousin is Duncan Tonatiuh's first children's picture book and it is a delight. His real-life experiences in the culture of New York City and in rural Mexico give élan to the activities of these two cousins. The illustrations, according to the author, were inspired by the ancient art of Mexico. The story affirms and celebrates cross-cultural experiences in a time when there is still plenty of xenophobia afoot in America. That is one of the reasons why this simple and sweet tale of sharing is so relevant and needed right now. Affirming commonalities is the spiritual practice of unity and it is at the heart and soul of this children's book.