The presence of multiple cancers in one patient has excited the interest of many investigators, and considerable literature has accumulated on this subject. The scientific concepts and clinical importance of field cancerization are the subject matter of this book. This book is a compendium of importance to oncologists and cancer researchers and caregivers. Existent knowledge on cancer biology and therapy has been vastly expanded by this concept of cancer evolution. Expanding "super-competitors", multi-step carcinogenesis, and stem cell theories are some novel mechanistic models of carcinogenesis discussed in this book. Extensively covered in this book as well, are the cellular and molecular changes representative of field cancerisation in several cancers, including haematologic and paediatric cancers.