This book provides an updated research materials about the hair and skin roles in development of a normal individual. It enlightens the genetics, morphology and physiology of hair and skin appendages. Two major genetic disorders; Alopecias and Ectodermal Dysplasias are discussed here with experimental investigations of multiples affected families. Techniques used here involve the clinical studies, genotyping, sequencing and also the expression analysis. It portrays that how any lethal mutant gene possessing expression in hair and skin can affect the normal development of an individual. It also focuses on the desired need of genetic counselling of affected and endangered families with genetic anomalies.