[en] The time scale of the fission process at moderate to high excitation energies is determined by shape-dependent and, most likely, temperature-dependent nuclear dissipation. Most of the present knowledge about the time scale of nuclear fission has been deduced from measurements of multiplicities and the energy spectra of neutrons, light charged particles, and γ-rays evaporated or emitted prior to and after scission. Together with complementary data such as fission probabilities, it is possible to obtain a reasonable description of the time evolution of nuclear fission. The magnitudes of nuclear dissipation, deduced from pre and postscission neutron multiplicities, are compared with the results of recent theoretical dynamical models. The status of the experimental results pointing to a relatively slow fission process and cold scission, as well as the corresponding theoretical interpretation of these findings, are reviewed. 53 refs., 13 figs