An experimental system was designed, built and used to determine the optical constants of matenals in the Vacuum Ultraviolet region of the electromagnetic spectrum. An optical analysis chamber was designed to mount onto the back end of an existing monochromatic VUV imaging beam system, which covers a wavelength range from 30-200nm. The chamber may accommodate three different expenmental configurations, allowing transmission and reflection measurements to be taken separately or at the same time. A versatile computational analysis system was developed to process the data obtained with this experimental system Recorded CCD images are aligned using a novel interpolation method, and reflection or transmission values are calculated from these. A Kramers-Kromg analysis program was developed and used to obtain a complete set of optical constants in the VUV region if reflection data is available over a sufficiently extensive wavelength range. The absorption coefficient of aluminium in the region between 30 and 85 5nm was determined to demonstrate the capabilities of the suite of expenmental and computational analysis systems. The absorption coefficient of aluminium is shrouded in controversy in this region of the spectrum due to two papers with conflicting results ref [19] & [21].