The articles in this issue of Spectrum are from a diverse range of voices, setting a new precedent for the publication. Former U.S. Republican Senator Jake Garn of Utah urges the United States to provide the leadership needed to stop the proliferation of nuclear weapons by permanently ending nuclear weapons testing and ratifying the CTBT. Talat Masood, former Secretary for Defence Production in the Ministry of Defence, Pakistan, outlines the near term and long term developments that will influence the nuclear landscape. Bharath Gopalaswamy, formerly of the Indian Space Research Organization and now at the Stockholm International Peace Research Institute (SIPRI), highlights the benefits of CTBTO membership and points out that States that have not signed the Treaty are at a disadvantage since they do not have access to verification data. Xia Liping from Tongji University in China explains why CTBT ratification is in China’s strategic interests. And Michel Nambobona, the Director General of the National Data Centre in the Central African Republic, outlines his personal role in helping to secure CTBT ratification by his nation.

Spectrum 15 also covers various verification-related issues. On-site inspection expert, Charles Carrigan, describes the evaluation of equipment during the CTBTO’s 2009 Noble Gas Field Operations Test (NG09) in Slovakia. And finally, our own infrasound experts describe some of the recent experiences gained by the infrasound network.