This is a book on Native American cultures of Puerto Rico prior to, and shortly after, the arrival of the Spanish in 1493. A book on the prehistory of a modern geopolitical entity is artificial. It is unlikely that prehistoric occupants recognized the same boundaries and responded to the same political forces that operated in the formation of current nations, states, or cities. Yet, archaeologists traditionally have produced such volumes and they generally represent anchors for ongoing research in a specific region, in this case the island of Puerto Rico, its immediate neighbors, and the wider Caribbean basin. To varying degrees, this work addresses issues and draws data from beyond the boundaries of Puerto Rico because in pre-Columbian times the water between islands likely was not viewed as a boundary in our modern sense of the term. The last few decades have witnessed a growth of intense archaeological research on the island, from material culture in the form of lithics, ceramics, and rock art; to nutritional, architecture, and environmental studies; to rituals and social patterns; to the aftermath of Conquest. ""Ancient Borinquen"" provides a comprehensive overview of recent thinking, new data, syntheses, and insights into current Puerto Rican archaeology, and it reflects and illuminates similar concerns elsewhere in the West Indies, lowland South America, and Central America.