Sequential effects are among the most robust phenomena observed in psychological experiments; judgments that may be made independently are influenced by prior judgments when made in a sequence, even when doing so is suboptimal. Over the years, models of sequential effects that are observed in categorization, recognition, absolute identification, and short-term priming experiments were developed by different researchers at different times, each apparently unaware of the others. Nevertheless, all models of sequential effects developed within the framework of the General Theory converged on the same assumption: information used to make one judgment carries over to influence the judgment made on a subsequent trial. These models and relevant data are presented.