The prevention of handicapping conditions and the reduction of failure and disaffection in schools is the topic of this booklet, one of 16 texts designed for use in an Open University course on the education of handicapped students in the United Kingdom. Medical approaches to prevention, including those involving ethical issues, are explored. Examples of primary, secondary, and tertiary prevention are given, and court cases are introduced to illustrate the range of ethical and moral considerations involved. In a section on at-risk children, development of screening procedures in schools is considered, as are preschool home intervention approaches and the underlying theories of compensatory education. Scottish attempts to reform the curriculum and school organization are cited as one example of efforts to change the educational system, thereby reducing the ill effects of school on children. A final section considers factors that limit change but also notes the possibility of positive change. The appendixes summarize reactions of Scottish teachers to their new roles and present a brief case study of a preschool community project in Scotland. (CL)