1 Introduction.- 2 Fundamentals of Effective Media and Diffractive Optics.- 3 Design of Bulk Optical Nanocomposites.- 4 Nanocomposites as Tunable Optical Materials.- 5 Achromatic Diffractive Optical Elements (DOEs) for Broadband Applications.- 6 The Potential of Nanocomposites for Optical Design.- 7 Outlook.- Appendix.