This note can be used as informational background reading on fuel cells, an environmentally attractive alternative technology for power generation and transportation. Courses that deal with innovation, technology, entrepreneurship, environment, energy/power/transportation issues, or sustainable business may find this useful. This note accompanies a case on fuel cells (UVA-ENT-0018). The note explores fuel cell technology including its history, current and potential applications, fuel sources, environmental issues, and manufacturing challenges. The commercialization issues covered include: performance requirements, time to market, costs, and other outside driving forces such as fuel distribution infrastructure, power generation reliability, fuel prices, etc. Fuel cells are an electrochemical energy source with the potential to take a significant market share from traditional electrical power generation and automobile propulsion technologies. Over the next decade fuel cells may provide more reliable energy and cleaner air while decreasing dependence on fossil fuels for transportation and stationary applications.