In 1948, Stanford scientists demonstrated the first microwave linac, which they used to accelerate electrons to nearly the speed of light for studies of fundamental physics. The technology used to make that early accelerator, which was about a yard long and required several people to carry it, was the basis for SLAC’s two-mile-long linac and many others to follow. Last year, a collaboration centered at SLAC and Stanford demonstrated a new type of particle accelerator which uses laser light to accelerate electrons within a finely patterned fused silica structure one millimeter long, a concept that has been colloquially referred to as an "accelerator on a chip." This tiny device generates accelerating fields that are 10 times stronger than those in today’s conventional accelerators, and an additional factor of 10 or more should be achievable by optimizing the design and materials. These developments may lead to a new generation of compact and affordable sources of energetic particles for high-energy physics exploration, biological and chemical science, and industrial and medical devices for cancer therapy, food sterilization and security.