Amelogenesis imperfecta (AI) is an inherited disorder that is associated with mutations in five genes (AMEL; ENAM; MMP20; KLK4 and FAM83H) with a wide range of clinical presentations (phenotypes). It affects the structure and appearance of enamel of all teeth, both in the primary and secondary dentition. In this review paper, we look at the epidemiology, classification, aetiology, clinical description and diagnosis of AI. In the following three papers of this series, we aim to describe the role of paediatric dentists, orthodontists and restorative dentists in the clinical management of patients with AI.