The best remembered aphorists have contrived to state new truths in brief and telling ways. Less fascinated than most authors with leaf, twig, and branch, they strike immediately for the pith. Almost every reader of their work first pays tribute to this concentration of effort with the repeated shock of joy and enlightenment that marks his response. It seems likely that such writers try to achieve a compression of statement that corresponds to the instantaneous character of their insights. Like Dante, they are stirred by the hope of economizing glimpses of eternity into single-worded statements; unlike him, they never quite despair of doing so. Anyone who has responded to the success of their efforts can appreciate the temptation to discover something about the means by which these paradoxical compositions achieve their effects, particularly those that time and again tumble their reader's complacency. It is with the ways in which those effects derive from the structural patterns of the aphorism that this essay is concerned. The method will be first to classify aphorisms according to structure and then to examine the ways in which each class affects the reader.