Recent experimental results for spontaneous fission half-lives and fis
sion fragment mass and kinetic-energy distributions and other properti
es of the fragments are reviewed and compared with recent theoretical
models. The experimental data lend support to the existence of the pre
dicted deformed shells near Z = 108 and N = 162. Prospects for extendi
ng detailed studies of spontaneous fission properties to elements beyo
nd hahnium (element 105) are considered.