The present volume and its companion, Boron in Soil and Plants: Reviews , contain details of late-20th century advances in boron nutrition. They are designed as references for researchers, university lecturers and graduate students. There is also sufficient practical information on the use of boron in agriculture, forestry and horticulture for advisers and fertilizer representatives to find these volumes valuable references. For agriculture, horticulture, and forestry, papers on the effectiveness of boron fertilizers and the selection of boron-efficient and boron-tolerant cultivars should attract interest. Physiologists should be interested in findings on the location of boron in cells, the function of boron in cell walls and the techniques used for these studies. Boron toxicity is a significant problem in many areas of the world. However, papers in the present volume challenge a long-held dogma of boron research that a narrow range exists between deficiency and toxicity of boron.