This book focused on whether the incidence of the pathogenic point mutation A3243G in the gene tRNALeu(UUR) indicating sub-type 2 diabetes mellitus also known as mitochondrial diabetes, is comparable within the Nigerian population to that reported in other populations. Nigeria is the most populous Black Country in the world; this provided a good platform for the investigation of genetic disorder in diabetes mellitus type 2. In addition, diabetes mellitus is becoming a public health concern in developing countries. Hence, the need for this publication. There are a lot of publications that have documented point mutation among patients with diabetes mellitus, especially among the Europeans but to the best of my knowledge, none from Africa except for this one. Therefore, this book is timely!