Brewster angle microscopy facilitates the observation of optical anisotropy in monolayers and multilayers of long-chain amphiphilic molecules. With new model calculations based on the 4 x 4 matrix formulation of Berreman we were able to distinguish between optical anisotropy induced by chain tilt and that caused by orthorhombic lattices. Thus long-range bond orientational order in monolayers and multilayers in a range of 100 mum could be identified.