For a long time, the Internet of Things initiative was driven by academics-developing embedded hardware, sensing algorithms, network protocols, software frameworks, applications, business scenarios, and interaction paradigms. Only recently industrial stakeholders realized the unparalleled potential of these technologies, instigating a paradigm shift that we refer to as the fourth industrial revolution. However, as this shift starts entering the mainstream and disrupting a multitude of business dynamics, it also uncovered myriads of challenges-some are technical, some are political, and some are ethical. In this special issue, together with our guest authors, we focus our attention on some of the daunting system development challenges in bringing bleeding-edge Internet of Things (IoTs) technologies to the real world. Each of the five articles featured in this issue tackles unique challenges associated with the deployment of real-world IoT systems.