Oncology is a field characterized as “medicine of high complexity” and cancer is generally regarded as a complex system. Therefore, it cannot be classified and treated according only to its biology. Even though research on the biology of cancer has increased and more studies have been published, the related sociological, political and economic dimensions, as well as mathematical models that predict whether this condition will take one course or another, have often been neglected. The Invisible Hand of Cancer—The Complex Force of Socioeconomic Factors in Oncology Today unfolds the variables behind the biological disease, exploring the social aspects and presenting cancer as a model inside of the Complexity Theory. Cancer is a generic word for more than 200 diseases. In a wider view of cancer treatment, the various factors of cancer interact in multiple ways and it is a difficult task to identify and understand all the possible combinations in this system. All these variables and how they interact can be defined as the invisible hand of cancer. This book does not intend to be an exhaustive analysis of these aspects. It is a door being opened to the cancer research journey, along the years and beyond its biology. It will also discuss how social behavior can interfere in the evolution of cancer treatment, as a result of society’s way of thinking and choices, thus the importance of truly addressing cancer as an intricate system and a public health issue. After the success of my children’s books about cancer (Chubby’s Tale: The true story of a teddy bear who beat cancer, Bald is Beautiful: A letter for a fabulous girl, Cancer Daily Life, and What is Cancer?: A book for kids), I have developed a passion for writing about science in a simple way for non-scientist readers. I have also worked to build a career as a writer, communicating with patients, advocates, and oncology and pediatric oncology professionals, mostly on Twitter. Everyone knows someone who has or had cancer, so more and more popular science books on this topic are becoming bestsellers. This book is directed to a general audience and follows scientific standards, encompassing high-quality data, but in an easy-to-read format. Furthermore, it will raise awareness and show how simple actions such as not judging patients and not spreading false popular beliefs can contribute to achieve a new milestone in the cancer journey.