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 Bulletin of the Atomic Scientists since 1987. This issue’s column examines the US nuclear arsenal, which remained roughly unchanged in the last year, with the Department of Defense maintaining an estimated stockpile of nearly 3,800 warheads. Most of these warheads are not deployed; approximately 2,050 warheads are held in reserve and approximately 2,385 retired warheads are awaiting dismantlement, giving a total inventory of approximately 6,185 nuclear warheads. Of the approximately 1,750 warheads that are deployed, roughly 1,300 are on ballistic missiles, 300 at strategic bomber bases in the United States, with another 150 tactical bombs deployed at European bases. The Nuclear Notebook is always free-access in the Bulletin‘s subscription magazine.