While there is much in the literature on ESL development, this book is the first of its kind to track the development of specific language abilities in an Intensive English Program (IEP) longitudinally and highlights the implications of this particular study’s findings for future IEP implementation and practice and ESL and SLA research. The volume draws on many years’ worth of data from learners at an IEP at the University of Pittsburgh to explore selected aspects of language development, including lexical, grammatical, speaking, and writing abilities, in addition to placement assessment practices and student learning outcomes. A concluding chapter points to the ways in which these findings can be applied to decision making around IEP curriculum development and the future role of IEPs in higher education more broadly. With its focus on students in IEP settings and the concentration on data from students evaluated over multiple semesters, this volume offers a unique opportunity in which to examine longitudinal developmental patterns of different L1 groups on a variety of measures from the same learners and will be key reading for students and researchers in second language acquisition, English for Academic Purposes, language education, and applied linguistics.