This book addresses some surveys on oscillators essentially dedicated to nanoscale circuits, with, a special emphasis on DGMOS; indeed, this later one seems the most relevant device to build nano-osclllators, especially for 3D integration and highly submicronic MOS compatibility. After recalling essential items on noise theory, we choice some demonstrator devices as SiGe heterojunction bipolar transistor (HBT) realized in a standard BiCMOS process, but with a nanometric base thickness, as an active device. Resonant Tunnelling Diode and Single Electrical transistor are also grasped, although we think these two later devices cannot be integrated easily with the late CMOS technologies because, for instance, of impedance or temperature adaptation drawbacks. This book serves as a reference for advanced graduates or researchers in the field of micro and nano electronics interested in topics relevant to and its the noise domain, at device or circuit and system levels.