The scope of this volume of Progress in Molecular Biology and Translational Science includes the molecular regulation of olfactory processes in vertebrates and insects including detailed discussion of olfactory proteins, signaling cascades and olfactory receptor modeling. In addition, because insect olfaction is an important and emerging field, it is also discussed in the context of key research questions such as disruption of host-finding by insect disease vectors, elucidation of the diverse range of compounds that are detected by insects, and the detection of pheromones by moths.