Selective cytoplasmic organelle and protein targeting has long been thought to constitute the sole determinant of cell polarity and complexity. This view has been changed, however, by the discovery of differential subcellular RNA distribution patterns. Over the past decade it has become clear that selective mRNA sorting and translation contributes to an accumulation of cognate proteins at discrete cellular sites. In this book, various systems are discussed (e.g. Xenopus oocytes, mammalian brain, invertebrate nervous system) in terms of RNA trafficking, RNA-targeting sequences (cis-elements) and RNA-transporting proteins (trans-factors), activity-dependent translational regulation and the significance of the cytoskeleton for neuronal function and plasticity. It also discusses nucleocytoplasmic export of mRNA and viral RNA as another example of subcellular RNA kinesis.