Photonic structures occurring in biological tissues such as butterfly wings, beetle elytra or fish scales are responsible for a broad range of optical effects including iridescence, narrow-band reflection, large solid-angle scattering, polarization effects, additive color mixing, fluid-induced color changes, controlled fluorescence. Studies have provided understanding of the underlying optical mechanisms and the biological functions as well as inspiration for the design and development of novel photonic devices, also called bioinspiration. In this forward-thinking book, the research related to photonic structures