This review addresses the three basic principles of person-environment fit theory: ( a ) The person and the environment together predict human behavior better than each of them does separately; ( b ) outcomes are most optimal when personal attributes (e.g., needs, values) and environmental attributes (e.g., supplies, values) are compatible, irrespective of whether these attributes are rated as low, medium, or high; and ( c ) the direction of misfit between the person and the environment does not matter. My review of person-job and person-organization fit research that used polynomial regression to establish fit effects provides mixed support for the explanatory power of fit. Individuals report most optimal outcomes when there is fit on attributes they rate as highest, and they report lowest outcomes when the environment offers less than they need or desire. Linking these findings to individuals' abilities and opportunities to adapt, I reconsider fit theory and outline options for future research and practice.