Research and development of polymer-based nanocomposites/ nano-filled polymers is a rapidly expanding field of contemporary research because of the immense industrial, commercial and engineering applications these nanostructures can afford to have. The book features the advances in the field of fabrication and characterization of polymer matrix nanocomposite films. A systematic analysis of the growth as well as structure and morphology, linear and nonlinear optical (NLO) properties of low cost organic-polymeric nanocomposites, fabricated by incorporating different organic dyes into poly(vinyl alcohol) (PVA) template, is demonstrated. Investigations on understanding structure-property relationships and laser-matter interactions are given special emphasis with a view to design and develop further advanced materials. The study also reveals tremendous scope for utilizing these novel nanocomposites, all of which exhibited nonlinear absorption and nonlinear refraction behavior, for applications in optical limiting, pulse shaping, optical data storage, optical switching etc.