Temperature correlations in a finite universe

We study the effect of a finite topology on the temperature correlations of the cosmic microwave background in a flat universe. Analytic expressions f or the angular power spectrum are given for all possible finite flat models . We examine the angular correlation function itself, pointing out visible and discrete features that arise from topology. While observations of the p ower spectrum on large angular scales can be used to place bounds on the mi nimum topology length, cosmic variance generally restricts us from differen tiating one flat topology from another. Schemes that acknowledge anisotropi c structures, such as searches for ghosts, circles or geometric patterns, w ill be needed to probe topology further.