Negotiation with non-ideological ethno-nationalist terrorists is more common and more successful than with other kinds of terrorists. Additional strategies for dealing with terrorists include combating, isolating, and mainstreaming. There are many arguments against negotiation with terrorists, but most of them do not apply to secret backchannel talks, which are usually the method of choice in first approaching these groups. The success of negotiation depends on the development of flexibility by both the terrorists and the authorities. These and other points are illustrated with case materials from the Northern Ireland peace process, and the analysis is extended, on a speculative basis, to negotiation with several Islamic terrorist groups.