This book introduces a new design technique that is called All-Time-On CMOS logic. This design technique is suitable for designing high speed digital circuits. This new design technique is applied in the disegn of a MUX and a DMUX. Both the MUX and the DMUX are designed to operate at 15 Gb/s and fabricated on 0.18 um CMOS technology. The new design technique proves its ability to achieve more speed in digital circuits compared to conventional desgin techniques.