||The use of visual symptoms to identify nutrient deficiencies and toxicities in plants can be improved by both their careful observation and description. This guide attempts to accurately describe symptoms of nutrient deficiencies and toxicities in wheat (Triticum spp.). An effort has also been made to develop criteria for distinguishing one nutrient deficiency or toxicity from another using these visual symptoms. Expression of visual symptoms of a nutrient deficiency or toxicity may change with the variety. Although many of the 47 photos in this publication depict a single variety subjected to various nutrient deficiencies and toxicities, it is felt that the descriptions of symptoms presented will be of considerable value for diagnosing nutrient deficiencies and toxicities in other varieties of wheat. This booklet is designed as a quick guide for identifying these toxicities and deficiencies in the field. It is intended primarily for agricultural researchers, technicians, and farmers in developing countries, but also will be of value to others. The text comprises a brief description of the major nutrient deficiencies and toxicities in wheat. Color photographs, a diagnostic key for identifying deficiencies in the center of the guide, and a set of appendices complement the text as an aid to identification. Except where indicated, the photographs are provided courtesy of the authors.