Nerve growth factor (NGF), is a small secreted protein which induces the differentiation and survival of particular target neurons (nerve cells). It is perhaps the prototypical growth factor, in that it is one of the first to be described - that work by Rita Levi-Montalcini and Stanley Cohen was rewarded with a Nobel Prize. NGF is critical for the survival and maintenance of sympathetic and sensory neurons. NGF is released from the target cells, binds to and activates its high affinity receptor (TrkA), and is internalised into the responsive neuron. There are some data that show that NGF can be transported from the axon tip to soma, but it is unclear if this is necessary for effective cell signalling; in fact there are data showing that it is not. What is clear is that NGF binding and activation of TrkA is required for NGF-mediated neuronal survival and differentiation. This volume presents important recent research in this rapidly-expanding field.