Preferred frame effects in binary pulsar systems

We have analyzed preferred frame effects for binary orbits of arbitrary eccentricity. Unlike previous studies, we have considered these effects as perturbations over the general relativity post-Newtonian orbits. A number of new orbital preferred frame effects are discovered and we indicate how these can be used with the binary pulsar data to derive constraints on the two preferred frame parameters $\\alpha\sb1$ and $\\alpha\sb2.$ In the later part of the thesis we show that the traditional limiting procedure under which equivalence principles are supposed to hold true in general relativity, namely the local system getting successively smaller, is not valid when couplings of the local electric and gravitational fields to the background curvature are taken into account. We argue that the \u27Spectator Body Limit\u27 as formulated by K. Nordtvedt is the correct limiting procedure that shows equivalence principles to be valid in general relativity