Summary form only given. The availability of wireless transceivers transmitting over ranges from few microns to less than half a meter opens the door for a wide range of exciting new applications, ranging from seamless system assembly, smart surfaces, healthcare monitoring and intelligent machinery and components. However, the implementation challenges in terms of size and power for most of these applications are pushing the limits. Fortunately, by exploring the wide range of options offered to the designer, extremely small and virtually zero-power transceivers are feasible. This paper discusses the opportunities, challenges and options of short distance wireless, and illustrates the proposed techniques with several design examples. In addition, the challenges that emerge when trying to embed these nodes into very dense networks are explored. Special consideration is given to the issues of distributed synchronization, localization and robust communication.