The International Institute for Strategic Studies (IISS), a registered charity with offices in Washington, London, Manama and Singapore, is the world's leading authority on political-military conflict. It is the primary independent source of accurate, objective information on international strategic issues. Publications include The Military Balance, an annual reference work on each nation's defence capabilities; Strategic Survey, an annual review of world affairs; Survival, a bi-monthly journal of international affairs; Strategic Comments, an online analysis of topical issues in international affairs; and the Adelphi series of books on issues of international security.