Sculptured thin films (STFs) are nanoengineered materials with columnar morphology tailored to elicit desired optical responses upon excitation. The identical nanowires comprising a STF are oriented (nominally) parallel to each other, and possess two-- and/or three--dimensional shapes. Two canonical forms of STFs have been formalized. Linear constitutive relations for general STFs as unidirectionally nonhomogeneous (continuously or piecewise uniformly) and locally bianisotropic continuums are presented, along with a 4 x 4 matrix
ordinary differential equation for wave propagation therein. A nominal model for the macroscopic properties of linear STFs has been devised from using local homogenization. Several advanced as well as emerging applications of STFs are also discussed.