Fry's later reputation as a critic rested upon essays he wrote on Post-Impressionist painters. and his most important theoretical statement is considered to be "An essay in Aesthetics", one of a selection of Fry' s writings on art extending over a period of twenty years published in 1920. In "An essay in Aesthetics", Fry argues that the response felt from examining art comes from the form of an artwork; meaning that it is the use of line, mass, colour and overall design that invokes an emotional response. His greatest gift was the ability to perceive the elements that give an artist his significance.