“To the Non-Proliferation Treaty, was based on a firm conviction that there can be peace only through the elimination of all nuclear weapons, moved towards the limitation of nuclear armaments and other weapons of mass destruction, are important steps in creating an atmosphere of trust and the relaxation of tensions.”

Quoted in https://www.bbc.com/news/av/world-europe-50265870/mikhail-gorbachev-tells-the-bbc-world-in-colossal-danger Mikhail Gorbachev tells the BBC: World in ‘colossal danger’, BBC World News,(4 November 2019)
2000s

"Introduction: Thinkability"
Einstein's Monsters (1987)

Saving Ourselves From Self-Destruction (2004)

"Reaching Global Zero" (8 March 2011) http://www.huffingtonpost.com/valerie-plame-wilson/nuclear-proliferation_b_832399.html
Context: Without doubt, terrorist groups are trying to buy, build or steal a bomb. Furthermore, there is enough highly-enriched uranium (HEU) in the world to build more than 100,000 weapons, and rogue individuals are selling technology on the black market. If terrorists get hold of HEU, they could not be prevented from smuggling it into a targeted city, building a bomb and exploding it.
To my mind, the only realistic solution to this danger is to lock down all nuclear materials and eliminate all nuclear weapons in all countries: Global Zero. I am now dedicated to achieving this goal as a leader of the Global Zero movement. This movement was launched in December 2008 in Paris by an international group of 100 current and former heads-of-state, national security officials, military commanders and business, civic and faith leaders — and in just two years has grown to 300 leaders and 400,000 citizens worldwide.
The group believes that whatever deterrent value nuclear weapons had in the Cold War is now outweighed by the dangers of proliferation and nuclear terrorism. Our international Global Zero Commission has developed a practical, step-by-step plan to eliminate all nuclear weapons through phased and verified reductions.
To build on the progress made to date, we need a worldwide public movement to make Global Zero an urgent global imperative — and to bring all nuclear weapons countries to the table to negotiate multilateral nuclear arms reductions for the first time in history.

"Peace as a Civil Right" from A Prayer for America (2003) [Nation Books, ISBN 1-56025-510-2], p. 76

"Reaching Global Zero" (8 March 2011) http://www.huffingtonpost.com/valerie-plame-wilson/nuclear-proliferation_b_832399.html
Context: Without doubt, terrorist groups are trying to buy, build or steal a bomb. Furthermore, there is enough highly-enriched uranium (HEU) in the world to build more than 100,000 weapons, and rogue individuals are selling technology on the black market. If terrorists get hold of HEU, they could not be prevented from smuggling it into a targeted city, building a bomb and exploding it.
To my mind, the only realistic solution to this danger is to lock down all nuclear materials and eliminate all nuclear weapons in all countries: Global Zero. I am now dedicated to achieving this goal as a leader of the Global Zero movement. This movement was launched in December 2008 in Paris by an international group of 100 current and former heads-of-state, national security officials, military commanders and business, civic and faith leaders — and in just two years has grown to 300 leaders and 400,000 citizens worldwide.
The group believes that whatever deterrent value nuclear weapons had in the Cold War is now outweighed by the dangers of proliferation and nuclear terrorism. Our international Global Zero Commission has developed a practical, step-by-step plan to eliminate all nuclear weapons through phased and verified reductions.
To build on the progress made to date, we need a worldwide public movement to make Global Zero an urgent global imperative — and to bring all nuclear weapons countries to the table to negotiate multilateral nuclear arms reductions for the first time in history.

Saving Ourselves From Self-Destruction (2004)
Context: Nuclear proliferation is on the rise. Equipment, material and training were once largely inaccessible. Today, however, there is a sophisticated worldwide network that can deliver systems for producing material usable in weapons. The demand clearly exists: countries remain interested in the illicit acquisition of weapons of mass destruction.
If we sit idly by, this trend will continue. Countries that perceive themselves to be vulnerable can be expected to try to redress that vulnerability — and in some cases they will pursue clandestine weapons programs. The supply network will grow, making it easier to acquire nuclear weapon expertise and materials. Eventually, inevitably, terrorists will gain access to such materials and technology, if not actual weapons.
If the world does not change course, we risk self-destruction.

Source: 2010s, 2016, September, First presidential debate (September 26, 2016)

Speech at a Soviet Official banquet http://www.margaretthatcher.org/speeches/displaydocument.asp?docid=106776, St George's Halls, the Kremlin (30 March 1987)
Second term as Prime Minister