This is an annual assessment of Department of Defense (DOD) weapon system acquisitions, an area that has been on GAO’s high-risk list for more than 20 years. The report includes observations on (1) the cost and schedule performance of DOD’s 2012 portfolio of 86 major defense acquisition programs, including the Missile Defense Agency’s Ballistic Missile Defense System; (2) the knowledge attained at key junctures in the acquisition process for 40 major defense acquisition programs that were selected because they were in development or early production; and (3) key acquisition reform initiatives and program concurrency. Major defense acquisition programs are DOD’s costliest weapon system development and procurement programs. Tables and figures. This is a print on demand report.