James Marcum provides an analysis of the fundamental concepts that constitute the foundations of contemporary systems biology. These concepts include holism, emergentism, and robustness, and are compared to the concepts, reductionism, mechanism, and homeostasis, which form the foundations of molecular biology. In an introductory chapter, a brief history of systems biology is reconstructed, along with the issues surrounding the definition and methodology of systems biology, and a discussion of chaos and complexity theories and their relationship to systems biology. Also included in the chapter is a discussion of whether contemporary systems biology represents a Kuhnian paradigm shift or scientific revolution. In the next three chapters, the fundamental concepts of holism, emergentism, and robustness are examined in detail. The notion of holism is discussed first, since it is the major characteristic of systems biology. It is developed in response to the notion of reductionism, which historically is the main approach to the investigation of complex natural phenomena. The notion of emergence is explored in the next chapter and entails the process by which complex phenomena and their properties appear at higher levels of organisation. It is compared to the notion of mechanism, which molecular biologists use to explain ultimately natural phenomena. The final fundamental concept, robustness, is discussed in a following chapter and is contrasted to the notion of homeostasis. It refers to the functional capability or property of a system to maintain its integrity and performance in response to either internal or external perturbations or disturbances, which could compromise a system's stability. In a fifth chapter, cancer is used as a case study to exemplify systems biology's conceptual foundations as applied to disease. In a penultimate chapter, the challenges facing systems biology are discussed, along with the challenges facing its application to cancer biology. In a concluding chapter, the question is addressed whether systems biology is a revolutionary replacement of molecular biology for investigating and understanding biological phenomena.