This book presents design of a low power high speed 1-bit ALU in 45nm CMOS technology. Low power high speed circuit design has emerged as a challenging and an emerging field among circuit designers and researchers. A 1-bit ALU is designed in 45nm CMOS technology by using CMOS, nMOS PTL and GDI circuit techniques and its performance characteristics such as power dissipation, delay, power-delay product and number of transistors are compared. GDI technique provides better performance characteristics for designing a low power high speed VLSI circuit. This circuit technique reduces power dissipation, delay, and it also maintains low complexity in the integrated circuit design. This technique is suitable for designing a low power high speed VLSI circuit by using very less number of transistors as compared to other circuit design techniques. This technique has emerged as an effective circuit technique for designing a low power high speed VLSI circuit. The contributions made in this book would help circuit designers and researchers in designing low power high speed integrated circuits.