The United States has been developing and deploying ballistic missile defenses (BMD) to defend against enemy missiles continuously since the late 1940s. Chapter 1 gives a brief history of the BMD Program. For over half a century, the Department of Defense (DOD) has funded efforts to defend the United States from ballistic missile attacks. The Missile Defense Agency (MDA) developing missile defense capabilities to defend the United States, deployed forces, and regional allies from missile attacks. Chapter 2 addresses for fiscal year 2018 (1) the progress MDA made in achieving delivery and testing goals and (2) the extent to which MDA made progress in developing and delivering integrated regional BMDS capabilities. Chapter 3 discusses (1) the challenges MDA and the defense intelligence community face in meeting the agency's threat assessment needs and (2) the extent to which MDA engages the defense intelligence community on missile defense acquisitions. Foreign countries have made advancements in their nuclear weapons and ballistic missile programs. Chapter 4 reports on the current status of North Korea's nuclear weapons and ballistic missile programs, while chapter 5 provides information on Iran's ballistic missile capabilities. Members of Congress and Pentagon officials have placed a growing emphasis on U.S. programs to develop hypersonic weapons as a part of an effort to acquire the capability for the United States to launch attacks against targets around the world in under an hour. Chapter 6 focuses, primarily, on the Pentagon's ongoing program to develop ballistic missile-based conventional prompt strike systems. The Navy undertook a conceptual design phase for the FFG(X) Guided Missile Frigate program that enabled industry to inform FFG(X) requirements, identify opportunities for cost savings, and mature different ship designs. Chapter 7 addresses the FFG(X) acquisition approach and contracting plans. Chapter 8 provides background information and issues for Congress on the Aegis ballistic missile defense (BMD) program, which is carried out by the Missile Defense Agency (MDA) and the Navy, and gives Navy Aegis cruisers and destroyers a capability for conducting BMD operations.