This book highlights information from a project that focused on where and how content-based English-as-a-Second-Language (ESL) instruction has been implemented in pre-K through Grade 12 classrooms in public schools across the United States. A database was constructed of 3,000 public schools that have content-ESL programs. Descriptions of the programs were obtained through two questionnaires, by telephone, and from 2-day site visits conducted at 20 schools. The book is based primarily on the field reports of the 20 site visits but contains, in addition, highlights of the survey. It is for educators interested in learning more about content-ESL programs in other schools and provides information on designing a program, implementing or modifying a program, or sustaining an existing program. Part 1 describes the students who were observed and interviewed for the study; actions taken to meet federal, state, and district-level mandates; in-take, placement, and exit procedures; program designs; and curricula used at the school sites. Part 2 observes how teachers make content and language modifications and use a variety of resources to help students acquire academic concepts. The use of native languages and cultures in instruction and the assessment tools used to measure students' content achievement and English proficiency are discussed. Part 3 looks at what the site schools are doing in the way of professional development and community involvement. (Contains 54 references.) (VWL)