It's been called the most ambitious laser project ever, a nuclear weapon deterrence insurance policy, a portal into the heart of a star and a source for inexhaustible energy. Under construction at Lawrence Livermore National Laboratory, the National Ignition Facility (NIF) will attempt to direct 192 beams at a pea-sized spherical pellet containing deuterium and tritium suspended at the center of a 10-m diameter target chamber. The result is a small-scale nuclear explosion that releases radiation across the entire electromagnetic spectrum. This radiation mimics a thermonuclear explosion, providing a test arena for parts of an aging nuclear bomb or theories on the inner working of stars. The most publicized benefit, however, is that fusion energy represents an almost inexhaustible supply of electrical energy without the long-lived radiation wastes generated by fission reactors. On one hand, the $1.2 billion project could help to ensure the readiness of the US nuclear arsenal and, possibly, deliver the world to a new era free of dependence on fossil fuels. On the other, Livermore scientists must exert phenomenal control of the world's largest laser if it ever hopes to succeed.