Costa Rica: A Traveler's Literary Companion edited by Barbara Ras is a useful anthology — short fiction and essays by Costa Rican writers covering the country's landscapes, people, and politics. A good introduction to how Costa Ricans see their own country.
The Ticos: Culture and Social Change in Costa Rica by Mavis Biesanz, Richard Biesanz, and Karen Biesanz is a sociological portrait of the country written with unusual warmth and specificity. It covers family life, politics, religion, and the national identity questions that Costa Rica wrestles with — the "tico" character, as it's called — in a way that illuminates everything you see on the street.
Vida y Obra de Magón — José Marín Cañas — Costa Rica's 20th-century literary tradition runs through figures like Joaquín Gutiérrez, Carmen Lyra, and Yolanda Oreamuno, but the easiest entry point for Spanish readers is through the satirist Manuel González Zeledón (pen name "Magón"), whose short stories about San José life in the early 20th century are sharp and still funny.
1492: The Conquest of Paradise by Kirkpatrick Sale is not specifically about Costa Rica but covers the broader encounter between Europe and the Americas that shaped the entire region. It is polemical but well researched, and it gives necessary context for understanding the colonial legacies visible throughout San José.