Missile defense
The focal point for consultation on full-scale missile defense is the Reinforced Executive Working Group. The CNAD is responsible for conducting technical studies and reporting the outcome to the Group.
The NRC Ad hoc Working Group on TMD is the steering body for NATO-Russia cooperation on theater missile defense.
In September 2018, a consortium of 23 NATO nations met to collaborate on the Nimble Titan 18 integrated air and missile defense (IAMD) campaign of experimentation.

Missile defense: By early 2010, NATO will have an initial capability to protect Alliance forces against missile threats and is examining options for protecting territory and populations. This is in response to the proliferation of weapons of mass destruction and their delivery systems, including missiles of all ranges. NATO is conducting three missile defense–related activities:

Active Layered Theater Ballistic Missile Defense System capability: Active Layered Theater Ballistic Missile Defense System is "ALTBMD" for short.
As of early 2010, the Alliance has an interim capability to protect troops in a specific area against short-range and medium-range ballistic missiles (up to 3,000 kilometers).
The end system consists of a multi-layered system of systems, comprising low- and high-altitude defenses (also called lower- and upper-layer defenses), including Battle Management Command, Control, Communications and Intelligence (BMC3I), early warning sensors, radar, and various interceptors. NATO member countries provide the sensors and weapon systems, while NATO has developed the BMC3I segment and facilitate the integration of all these elements.

Missile Defense for the protection of NATO territory: A Missile Defense Feasibility Study was launched after NATO's 2002 Prague summit. The NATO Consultation, Command and Control Agency (NC3A) and NATO's Conference of National Armaments Directors (CNAD) were also involved in negotiations. The study concluded that missile defense is technically feasible, and it provided a technical basis for ongoing political and military discussions regarding the desirability of a NATO missile defense system.
During the 2008 Bucharest summit, the alliance discussed the technical details as well as the political and military implications of the proposed elements of the US missile defense system in Europe. Allied leaders recognized that the planned deployment of European-based US missile defense assets would help protect North American Allies, and agreed that this capability should be an integral part of any future NATO-wide missile defense architecture. However, these opinions are in the process of being reconstructed given the Obama administration's decision in 2009 to replace the long-range interceptor project in Poland with a short/medium range interceptor.
Russian Foreign Minister Sergei Lavrov has stated that NATO's pattern of deployment of Patriot missiles indicates that these will be used to defend against Iranian missiles in addition to the stated goal of defending against spillover from the Syrian civil war.

Aegis-based system: In order to accelerate the deployment of a missile shield over Europe, Barack Obama sent ships with the Aegis Ballistic Missile Defense System to European waters, including the Black Sea as needed.
In 2012 the system will achieve an "interim capability" that will for the first time offer American forces in Europe some protection against IRBM attack.  However, these interceptors may be poorly placed and of the wrong type to defend the United States, in addition to American troops and facilities in Europe.
The Aegis ballistic missile defense-equipped SM-3 Block II-A missile demonstrated it can shoot down an ICBM target on 16 Nov 2020.

ACCS Theater Missile Defense 1: According to BioPrepWatch, NATO has signed a 136 million euro contract with ThalesRaytheonSystems to upgrade its current theater missile defense program.
The project, called ACCS Theater Missile Defense 1, will bring new capabilities to NATO's Air Command and Control System, including updates for processing ballistic missile tracks, additional satellite and radar feeds, improvements to data communication and correlation features. The upgrade to its theater missile defense command and control system will allow for NATO to connect national sensors and interceptors in defense against short and medium-range ballistic missiles. According to NATO's Assistant Secretary General for Defense Investment Patrick Auroy, the execution of this contract will be a major technical milestone forward for NATO's theater missile defense. The project was expected to be complete by 2015.  An integrated air and missile defense (IAMD) capability will be delivered to the operational community by 2016, by which time NATO will have a true theater missile defense.

Defense systems and initiatives: Akash missile surface-to-air missile defense system
Arrow missile
Chū-SAM (中SAM) Japan's JGSDF Medium-Range Surface-to-Air Missile
David's Sling
HQ-9 regional air defence/anti-ballistic missile
IAMD The SMDC is leading the United States Army's laser efforts to replace MIM-104 Patriot.
Indian Ballistic Missile Defense Program
Iron Dome
Italian-French SAMP/T missile air defense system
KS-1 regional air defence missile
L-SAM
Medium Extended Air Defense System (MEADS)
Patriot surface-to-air missile system
Hawk medium range surface-to-air missile (SAM) system
RIM-161 Standard Missile 3
Russian A-135 anti-ballistic missile system
S-400 Triumf
Skyguard chemical laser-based area defense system proposed by Northrop Grumman
Sky Bow
Strategic Defense Initiative ("Star Wars")
Terminal High Altitude Area Defense (THAAD)
Vigilant Eagle Airport surface-to-air missile protection system
Iran Belief System 373 (Bavar-373)
Iran Arman long-range anti-ballistic missile system
Khordad 15

See also: Anti-satellite weapon
Command systems in the United States Army

References: 

Bibliography: Nicole C. Evans, "Missile Defense: Winning Minds, Not Hearts", Bulletin of the Atomic Scientists, September/October 2004.
Daniel Möckli, "US Missile Defense: A Strategic Challenge for Europe", CSS Analyses in Security Policy no. 12, April 2007.
Ishmael Jones, The Human Factor: Inside the CIA's Dysfunctional Intelligence Culture, New York: Encounter Books (2010) (ISBN 978-1594032233). Missiles intelligence.

External links: Missile Threat – CSIS Missile Defense Project
U.S. Ballistic Missile Defense Archived 6 May 2013 at the Wayback Machine A primer from the Council on Foreign Relations
Steven Donald Smith, Missile Defense Program Moves Forward, 2006.
Missile Defense: The First Seventy Years Archived 2015-09-22 at the Wayback Machine