Semiconductors comprising elements from groups II and VI of the periodic table and having a large energy gap (e g ZnSe) are generating intense R&D activity world—wide largely as a result of their blue green diodes. To review the accumulating knowledge and provide an up—to—date state—of—the—art picture 34 scientists from leading research groups in the USA, Europe and Japan have pooled their knowledge under the editorship of Dr. Bhargava. The book is illustrated, structured for reference and deeply indexed.