Neuroendocrinology is a branch of biology which is concerned with the functional and anatomical interactions between the endocrine system and the nervous system. Major neuroendocrine systems are hypothalamic-pituitary-adrenal axis, hypothalamic-pituitary-thyroid axis, hypothalamic-pituitary-gonadal axis and hypothalamic-neurohypophyseal system. Neuropeptide receptors are the G-protein coupled class that comprises of seven transmembrane receptors. Peptides are released into the synaptic cleft and they activate these receptors through high affinity binding and also mediate internal signaling events through cytoplasmic G-protein coupled effector. When these receptors are activated, this inhibits and activates a variety of second messenger systems which results in cell firing, phosphorylation and dephosphorylation events, modulation of membrane threshold and alteration of gene expression. This book covers in detail some existent theories about the role of neuropeptide receptors in neuroendocrinology. It presents researches and studies performed by experts across the globe. Students, researchers, experts and all associated with this field will benefit alike from this book.