This book provides background information and considers issues related to the worldwide proliferation of "precision strike" capabilities. Precision strike systems utilize projectiles, bombs, missiles, torpedoes, and other weapons that can actively correct for initial-aiming or subsequent errors by homing their targets or aim-points after being fired, released, or launched. Some analysts state that "the United States took an early lead in exploiting the promise of precision-strike systems and the use of precision weaponry has given the United States a battlefield edge for twenty years. However, these weapons are now spreading; other countries, and non-state actors, are acquiring them and developing countermeasures against them." The fact that this ability of the U.S. to project power could also diminish possibly leaving U.S. forces, and the U.S. itself, increasingly vulnerable to precision weapons in the hands of its adversaries, raises serious considerations for Congress.