The Nuclear Notebook is researched and written by Hans M. Kristensen, director of the Nuclear Information Project with the Federation of American Scientists, and Matt Korda, a research associate with the project. The Nuclear Notebook column has been published in the since 1987. This issue examines the status of the US nuclear arsenal. The US nuclear arsenal remained roughly unchanged in the last year, with the Defense Department maintaining an estimated stockpile of approximately 3,800 warheads. Of these, only 1,750 warheads are deployed, while approximately 2,050 are held in reserve. Additionally, approximately 2,000 retired warheads are awaiting dismantlement, giving a total inventory of approximately 5,800 nuclear warheads. Of the approximately 1,750 warheads that are deployed, 400 are on land-based intercontinental ballistic missiles, roughly 900 are on submarine-launched ballistic missiles, 300 are at bomber bases in the United States, and 150 tactical bombs are at European bases.