Philip Russell’s invention of photonic crystal fiber technology in 1991 opened a completely new field of research in photonics. He continues to be a leading authority in the field and has developed many key aspects of photonic crystal fiber technology, including endlessly single-mode “holey” fibers and hollow-core photonic bandgap fibers. Compared to traditional optical fiber, which is made from solid glass, photonic crystal fiber is typically microstructured with an array of hollow channels that allows tailored control of the light passing through the fiber, providing great flexibility. The fibers have found a wide range of unique applications, many of them pioneered by Prof. Russell, including broadband supercontinuum light sources, high-power fiber lasers, fiber-optic communications, scientific and medical imaging, microscopy, laser beam delivery, sensing, and pressure-tunable gas-based ultraviolet light sources.