Neurotrophic factors play essential roles in the developing and mature nervous system. Now more than 50 years old, this field of study continues to contribute breakthrough discoveries regarding the fundamental biology of cell-cell communication and the development and maintenance of the most complex and elegant biological machine - the brain. Neurotrophic factors influence cell proliferation, survival, differentiation, migration, axon and dendrite growth, synaptic plasticity and the interactions of neuronal and glial cells. They play critical roles in complex behaviors including feeding, anxiety, depression and learning. Studies of neurotrophic factors may have important implications for the treatment of a variety of neurological diseases including disorders of neural development and as well as diseases of the differentiated nervous system including Alzheimer's disease, Down syndrome, Parkinson's disease, Huntington's disease, epilepsy, stroke, and peripheral neuropathies. No venue for this field provides a better opportunity to learn of recent advances, and to encourage collaborations among scientists and students, than the Neurotrophic Factors Gordon Conferences. The 9th meeting promises to be the most exciting yet, featuring many different neurotrophic factors and their roles in neurogenesis, axon growth and guidance, survival, plasticity, behavior and disease. For the first time there will be sessions on the biology of stem cells and the new technologies for imaging nervous system function at the level of individual synapses, organelles and molecules. Emphasis will be placed on the most recent developments. Newly emerging hypotheses will be addressed, and opportunities to discuss groundbreaking work will be plentiful. Poster sessions and “Hot Topics” sessions will highlight cutting edge studies and enhance interactions. We envision this meeting as catalyzing important new efforts to translate neuroscience advances into effective new treatments for disorders of the nervous system.