This PDF covers the olfactory nerve (CN I) and provides an overview of how olfactory fibers function. Each part of the olfactory system is depicted in simplified diagrams, including the olfactory epithelium, nerve, bulb, and tracts, with supporting tables explaining the innervated structures. Topics include signal transduction, the pathway to the primary and secondary olfactory cortex, and clinical conditions, such as anosmia, dysosmia, and parosmia, supported by a stepwise breakdown of the entire pathway.