Serotonin or 5-hydroxytryptamine (5-HT) is a monoamine neurotransmitter. Biochemically derived from tryptophan, serotonin is primarily found in the gastrointestinal tract, platelets, and in the central nervous system (CNS) of animals, including humans. Discovered and crystallized over sixty years ago, serotonin operates as a short-range neurotransmitter as well as a long-range signalling modulator, with multiple effects on whole organism functions via plasma, platelet and neuroendocrine, gut, adrenal and other peripheral systems across many species. All of the important functions of serotonin in the brain and body were identified over the ensuing years by neurochemical, physiological and pharmacological investigations. Mainly, all these investigations have been performed via invasive methodologies, particularly in the CNS studies. Here we present a rapid overview of such methodological approaches focussing on voltammetry, one of the most recent technical approaches for serotonin analysis in vivo, in situ and in real time. Furthermore, we introduce a late technical evolution in the attempt to obtain in vivo non invasive measurement of brain serotonin.peer-reviewe