This book constitutes the proceedings of the fourth meeting in a series of topical conferences dealing with the process of nuclear fission, mainly at low excitation energy. Two chapters deal with the characteristics of one of the major fission observables, i.e. the fission fragments. The book also gives due attention to an often-neglected aspect of fission, the so-called ternary fission (i.e. fission accompanied by a charged light particle). Another chapter deals with fission barriers and cross sections and the link with astrophysics. Special attention is also given to recent applications such as accelerator-driven systems and transmutation. The last chapter discusses various interesting aspects of nuclear fission.