Book excerpt: Defective development of tooth enamel or dentin is a significant dental problem for children and adolescents in various respects, and dentists and other oral health workers find managing these problems challenging and stressful. While a considerable amount of relevant research is currently being undertaken, much further investigation is needed. This book discusses the known causes of defective dental enamel and explains why it is so difficult to restore. Most importantly, it presents the signs and symptoms that allow accurate diagnosis and documents the best contemporary management. The full range of enamel defects is considered, including defects in primary teeth and permanent teeth, associated syndromes, molar incisor hypomineralization, and genetic defects. The clinical chapters are well illustrated, providing clear guidelines for each procedure. In addition, avenues for future research are identified, with explanation of their rationale.