||Attosecond science is a branch of strong field physics that investigates ultrafast phenomena in nature. An attosecond (1 as = 10-18 as) is a characteristic time scale for the description of electron dynamics. The electron plays a key role in many phenomena: it determines molecular structure and bond formation; it relays information and is used in calculations in electronic devices, and it absorbs and emits radiation. The control of chemical processes, revolutions in communications and computing, and generation of novel light sources are areas of research that benefit from the study of ultrafast electron dynamics. The goal of attosecond science is to understand and manipulate ultrafast electron dynamics in a variety of materials such as atoms, molecules, and solids with the purpose of future applications.