The Magneto Optic Kerr Effect (MOKE) is a unique method to investigate the magnetization at the surface of the materials. The effect is based on the fact that the magnetization causes the interaction between the electrons in the material and the electric field of an incident light beam to be anisotropic. As a result, when a linearly polarized light beam is reflected from a magnetized surface, the reflected beam is elliptically polarized with the long axis rotated with respect to the direction of polarization of the incident light. The effect is already used in a number of applications; for instance reading information on hard disk drive devices. In this thesis, we present the MOKE instrument that we have designed and built at SQU. The instrument was built using mainly available redundant hardware. The specific data acquisition hardware and software was entirely designed and constructed for this project. The instrument is operational and can be used to obtain hysteresis loops as well as investigate the dynamics of magnetization reversal. A heating/cooling stage has also been constructed and incorporated in the instrument. The instrument was used to investigate the evolution of the hysteresis loop in (Co/Ni) multilayers as a function of the number, N, of repeats. The data presented shows that in the specimens with N = 4, 6 and 8 the ratio of the remanence to saturation magnetization MR/Ms is unity. The specimen (Co/Ni)4 displays a rapid magnetization reversal at the switching field, whereas the other two specimens have a gradual magnetization reversal. It is also observed that the switching field decreases as N increases.