The study of energy propagation and localization in optical lattices has become an important subject of research in several areas of science including mathematical physics, nonlinear optics and Bose-Einstein condensates. This book presents an original theoretical, numerical and experimental investigation of energy dynamics in nonlinear optical lattices. Theoretical work discusses nonlinear waves in both paraxial and nonparaxial regimes, the generation of solitons through nonlinear defects, the use of Lie groups in the study of ?universality? of physical models and finally ?accelerated? lattices with applications to dispersion spectroscopy. The numerical part consists in the realization of a nonlinear code to simulate light propagation in nematic liquid crystals, the latter being the material chosen for the experimental side of the work. Finally, experiments with voltage-driven nematic liquid crystals demonstrates tunable discrete diffraction, discrete solitons and their angular steering, multi-gap breathers and light driven Landau-Zener tunneling. The work discussed by this book led to the publication of 26 articles in peer-reviewed journals and 28 international conferences.