Herpes simplex virus (HSV) may be engineered to produce flexible and efficient gene delivery vectors. Recent advances in vector design and production have built on increasing understanding of the basic biology of HSV to minimise vector toxicity and exploit viral features that give rise to lifelong latent infection in the nervous system. In addition, the emerging picture of viral cell entry has allowed early steps to be taken towards targeting viral entry to predetermined cellular subsets. Recent work has established sound principles for the straightforward production of large-scale pure preparations of vector stocks for clinical applications.