The optical spectra of lithium niobate doped with cobalt were observed at room temperature and 77K. The absorption bands were identified using a theoretical energy level diagram. EPR spectra were obtained at 9 GHz and 4.2K. The observed spectra were explained with an axial spin Hamiltonian with an effective spin of 1/2. Holographic techniques were used to measure the laser-induced refractive index change at 514.5 and 488. nm. The holographic equipment and its operation are described in some detail.