Lasers play an increasingly important role in accelerator performance and are expected to provide the foundation for new techniques to make future facilities even more flexible and powerful. For example, they are currently used to produce polarized beam in an ion source, strip excess electrons from intense beams of H– ions, bunch beams to permit time slicing in light sources, perform pump-probe experiments that explore molecular dynamics at unprecedentedly short time scales, determine beam bunch parameters non-destructively, and create intense wake-fields in a plasma that can accelerate a witness beam with extraordinarily high gradients. While lasers are already essential for high-performance accelerators that support fundamental science and its applications, they are even more the key to the development of future accelerators, including compact systems for medicine, industrial applications, homeland security, and discovery science. Attributes in common to all future applications include the need for one or more of the following features: high peak power (i.e., high energy in a very short pulse); high average power (i.e., high repetition rate); and high electrical efficiency (i.e., cost-effective use of wall-plug power).