This manual provides background information in geotechnical engineering and design. It also includes guidance for performing geotechnical investigations, preparation of design recommendations, and submittal of the Geotechnical Report. It is based on past Indiana Department of Transportation (referred to herein as “INDOT” or “the Department”) experience, the experience of other groups and agencies with similar requirements, and the current state of the practice in geotechnical engineering. The intent is that this manual will stand on its own; however, to avoid unnecessary duplication, reference is often made to other available manuals and publications of the Department, as well as other references which are readily available. Additionally, since it is impractical to be totally encompassing, and since the state of the practice is continually evolving, some documents are simply referenced as needed.