How do contagions spread in population networks? Which group should we market to, for maximizing product penetration? Will a given YouTube video go viral? Who are the best people to vaccinate? What happens when two products compete? The objective of this tutorial is to provide an intuitive and concise overview of most important theoretical results and algorithms to help us understand and manipulate such propagation-style processes on large networks. The tutorial will contain three parts: (a) Theoretical results on the behavior of fundamental models; (b) Scalable Algorithms for changing the behavior of these processes e.g., for immunization, marketing etc.; and (c) Empirical Studies of diffusion on blogs and on-line websites like Twitter. We finally conclude with future research directions. The problems we focus on are central in surprisingly diverse areas: from computer science and engineering, epidemiology and public health, product marketing to information dissemination. Our emphasis is on intuition behind each topic, and guidelines for the practitioner.