Chapter 1. Methods for measuring nonlinear optical properties.- Chapter 2. Theoretical models for describing an enhancement in nanoscale optical nonlinearities for applications design.- Chapter 3. Study on second- and third-order nonlinear optical properties in nanostructured carbon allotropes.- Chapter 4. Study on second- and third-order nonlinear optical properties in metallic nanoparticles.- Chapter 5. Study on second- and third-order nonlinear optical properties in semiconductors nanoparticles and quantum dots.- Chapter 6. Study on second- and third-order nonlinear optical properties in nanostructured systems: nanocrystals and complex geometries.- Chapter 7. Applications, conclusions and perspectives.