This Diagnostic Report reflects the combined efforts of many dedicated individuals working on the numerous problems associated with the current changes in the Aral Sea and its drainage basin. It represents a consensus document, prepared on the basis of many, often diverse, deliberations of the Working Group of Experts for the Preparation of an Action Plan for the Rehabilitation of the Aral Sea Basin. Thus it should be viewed as a working document, comprising the best efforts of all those involved in its preparation. It also is noted that this report is the integration of individual components from many contributing authors. Accordingly, efforts were made to provide appropriate linkages between relevant topics and sub-chapters. Nevertheless, many of the contributing authors used differing styles and forms in preparing their materials. One such element is the use of references. Some contributors incorporated tables, figures and similar materials directly into the body of the text, without reference to their specific source. Others explicitly identified the sources of the materials used in their contributions. It also is noted that many of the references are available only in Russian.