This is the second edition of the book. Pediatric oncology refers to the study of childhood cancer. This book gives details on many aspects of pediatric oncology and the recent advances that have occurred on clinical levels. The aim of this book is to summarise the information that is available from randomised clinical trials in childhood cancer. This book reviews only the latest clinical trials in the filed of pediatric oncology. The details of these diseases were beyond the scope of this book. The authors commented briefly and generally on the diseases and the latest clinical trials for their treatment protocols only at the beginning of each main part of the book. However, there were no specific comments or authors'n views on the different conclusions of these clinical trials. These comments would have been very valuable to the reader, particularly in the diseases or areas where more than 20 clinical studies were presented with different opinions, outcomes and conclusions.