Human cancer is at an important frontier of medical research, and one where Computational Intelligence methods have made substantial inroads in recent years. Computational Intelligence research in cancer now reaches all biological scales from human population down to the phenotype and genotype. It is also fair to say that it reaches the complete range of cancer pathologies. This book does not aim to achieve such completeness of coverage. Instead, the studies included in it should provide readers with a broad palette and a hopefully useful taster of what Computational Intelligence methods can achieve in the field. This volume contains an overview of the field and a collection of eight leading-edge studies from research teams composed of experts in the field on various aspects of the subject.