This report shows that the face of the Puerto Rican population in the United States has changed dramatically in recent years. The analysis is based largely on data from the 1980 and 1990 Censuses of Population, but it is supplemented by other sources. The number of Puerto Ricans in the United States has increased from close to 2 million in 1980 to over 2.7 million in 1990, an increase spearheaded by massive emigration from Puerto Rico. The 1980s saw Puerto Ricans dispersing across the county, relocating from the traditional concentrations in eastern cities. New York remains the state with the largest Puerto Rican population, but the traditional association of Puerto Ricans with New York City is being replaced. Puerto Ricans experienced an astonishing rate of income growth in the period, with a great increase in labor force participation among women. Economic progress was tied to substantial improvements in educational attainment, with a dramatic drop in the number of Puerto Rican adults without a high school diploma, and an increase, from 17% to 29.3%, in the number of Puerto Ricans with at least some college education. In spite of this progress, the relatively high proportion of Puerto Ricans without a high school diploma remains a concern, as do inequities in the educational opportunities available to Puerto Ricans. Three appendixes discuss study methodology and statistical analyses. (Contains 2 figures, 53 tables, 2 appendix tables, and 28 references.) (Sld).