This book aims to be a comprehensive handbook covering the areas in which FHIT gene is important, addressing how its modification may be studied for academic and clinicopathological purposes and how it may be applied in therapeutic strategies. Until now, the field has lacked this type of organized source, but this current book, with contributions from many of the leading experts, makes good this absence. In this book, our aim is to analyze almost all biological prospectives of FHIT gene in order to develop various conclusions, we will discuss about the gene and protein structure, gene regulation, three-dimensional structure, and the relation of FHIT with various human cancers.