I elaborated these slides for an introductory class on Network Medicine given at UPV (Valencia) in October 2017. The fundamental principle behind Network Medicine is that disease phenotypes emerge from genotypes via the network properties of interactions between the underlying biological components. These phenotypes are best conceptualized as consequences of perturbations to disease modules of the biological networks in the cell, whether at the node level (disease genes) or the link level (disease edgotypes). With the further analysis of drug-disease association and drug-target association data, one can investigate the effects - therapeutic and undesired - of the associated medication. Understanding the molecular level networks allows to understand the connections between different diseases and the effects of drugs designed to target them, paving the way for personalized treatments based on one's own interactome.