Book excerpt: This issue of ECS Transactions covers state-of-the-art R&D results of the last 1.5 years in the field of semiconductor wafer bonding technology. Wafer Bonding Technology can be used to create novel composite materials systems and devices what would otherwise be unattainable. Wafer bonding today is rapidly expanding applications in such diverse fields as photonics, sensors, MEMS, X-ray optics, non-electronic microstructures, high performance CMOS platforms for high end servers, Si-Ge, strained SOI, Germanium-on-Insulator (GeOI), and Nanotechnologies.