The proliferation of lasers and systems employing lasers has brought with it the potential for adverse effects from these bright, coherent light sources. This includes the possibility of damage from pulsed lasers, as well as temporary blinding by continuous-waver lasers. With nearly every wavelength possible being emitted by these sources, there exists a need to develop optical limiters and tunable filters which can suppress undesired radiation of any wavelength. This book addresses a number of materials and devices which have the potential for meeting the challenge. The proceedings is divided into five parts. Parts I and II cover research in organic and inorganic materials primarily based on nonlinear absorption or phase transitions for optical limiting of pulsed lasers. Part III includes photo-refractive materials and liquid crystals which find primary applications in dynamic filters. Part IV covers various aspects of device and material characterization, including nonlinear beam propagation effects. Theoretical modelling of materials properties is the subject of Part V.