This report is a comprehensive information resource on the more than 514,000 international students in the United States and the more than 129,000 U.S. students who studied abroad in 1999. The Institute of International Education has conducted an annual statistical survey of the internationally mobile student population in the United States since 1948. The number of international students studying in the United States increased sharply during the 1999-2000 academic year. This year's total of 514,723 represents an increase of 4.8% over last year's figure. More than two-thirds of these students receive most of their funding for U.S. study from personal and family sources, and three-quarters receive most of their funding from sources outside the United States. The most significant source of U.S. funding is the institution the student attends. This year's enrollment increase reflects substantial increases from China and India, with enrollments growing at more than twice the overall rate. Asian students constitute more than half of the international enrollments. As the overall foreign student total has increased, community college international enrollments have grown by more than 40%. Business and management continue to be the most popular fields of study among international students in the United States. The past 3 years have also seen double digit enrollment increases in the number of U.S. students participating in study abroad programs for academic credit. Of these students, 45.9% study abroad in short duration programs. Information is also presented about the intensive study of English and the 74,571 foreign scholars who teach and conduct research in the United States. (Contains 19 figures and 38 tables.) (SLD)