sentences:  Heidenstam's chief contribution was the pamphlet, directed chiefly against Strindberg, "Proletärfilosofiens upplösning och fall" ("The Decline and Fall of the Proletarian Philosophy").Heidenstam's poetical collection "Nya Dikter", published in 1915, deals with philosophical themes, mainly concerning the elevation of man to a better humanity from solitude.He died at his home Övralid on 20 May 1940.