The aim of this dissertation is to perform pioneering precision measurements of the Casimir pressure at temperatures from 4K to 300K and in a distance range from 0.100 - 2 micrometers. To assure the completion of these objectives I have design and constructed a state-of-the-art apparatus especially design to operate under those circumstances. The results will deepen our understanding of a phenomenon that is a key factor in the future of nanotechnology and is the only evidence for the quantum fluctuations of the vacuum.