The only book of its kind in the English language, this is the first volume of the Oxford Commentaries on the State Constitutions of the United States to explore the constitution of a U.S. territory: Puerto Rico. The first half of the volume unearths the island's constitutional history from the days of Spanish colonization in the 16th century, through to Congress' enactment in 2016 of the Puerto Rico Oversight, Management and Economic Stability Act (PROMESA). Professor Cox Alomar offers a careful analysis of the most recent decisions of the U.S. Supreme Court implicating Puerto Rico, Sánchez Valle (2016), Franklin Trust (2016), Aurelius (2020) and Vaello Madero (2022). The second half of this volume provides an in-depth analysis of each of the provisions incorporated by the Puerto Rican framers to the 1952 Constitution, still in full force today. Commentary is provided on each of these constitutional provisions in light of the most recent decisions of the Puerto Rico Supreme Court. The volume examines the interaction between the Puerto Rico Supreme Court and the U.S. Supreme Court, as well as the complex relationship between Puerto Rico and the political branches in Washington. This book is a timely companion in one of the more complex, yet transformative periods in Puerto Rico's constitutional life.