Book excerpt: The Columbia (SSBN-826) class program is a program to design and build a class of 12 new ballistic missile submarines (SSBNs) to replace the Navy's current force of 14 aging Ohio-class SSBNs. The Navy has identified the Columbia-class program as the Navy's top priority program. The Navy wants to procure the first Columbia-class boat in FY2021. Research and development work on the program has been underway for several years, and advance procurement (AP) funding for the program began in FY2017. The Navy's proposed FY2020 budget requests $1,698.9 million in advance procurement (AP) funding and $533.1 million in research and development funding for the program. The Navy's FY2020 budget submission estimates the total procurement cost of the 12-ship class at $109.0 billion in then-year dollars. An April 2018 Government Accountability Office (GAO) report assessing selected major DOD weapon acquisition programs stated that the estimated total acquisition cost of the Columbia-class program is $102,075.3 million (about $102.1 billion) in constant FY2018 dollars, including $12,901.0 million (about $12.9 billion) in research and development costs and $89,174.3 million (about $89.2 billion) in procurement costs.