This book, Big Data and Software Defined Networks, aims to investigate areas where Big Data and SDN could help each other in delivering more efficient services. SDN can help Big Data applications to overcome one of their major challenges: message passing among cooperative nodes. Through proper bandwidth allocation and prioritization, critical surges of Big Data flows can be better handled to effectively reduce their impacts on CDCs. Big Data, in turn, could also help SDN controllers to better analyse collected network information and make more efficient decisions about the allocation of resources to different network flows.