Twenty-five years ago Dubna hosted the first meeting for experts on pulsed neutron sources (PNS). At that time the primary question was which type of intense neutron source should be built at the Laboratory of Neutron Physics (LNP) ofthe Joint Institute ForNuclearResearch (JINR). Preference was given to a repetitively pulsed reactor, IBR-2, which was constructed and put into operation in the early eighties. In the last 10 years effective spallation neutron sources (SNS) have been constructed throughout the world. Both typesof PNS (pulsed reactors and SNS) are complimentary to each other as instruments for physics research, but rnodern physics and technology need more effective neutron sources.