Memory has a central role in computing and is a current subject of research and large investments; in the last few decades, new technologies and architectures have been proposed to overcome the major limits of the currently available memories based on charge storage. Intel already launched on the market the first generation of Phase Change Memory based on an innovative storage mechanism that meets the requirements of the Storage Class Memory niche; other companies like ST Microelectronics are already developing PCM memories for Automotive and Embedded Markets. Alongside PCM, new types of selectors that are willing to replace CMOS that exploit different physical principles are making their way into the scene offering new and innovative solutions.