Femtosecond lasers, which have been considered difficult to operate, expensive, and sensitive, are breaking out of laboratories and are now being used in various large-scale applications. This book provides a fresh perspective on femtosecond lasers – discussing how the femtosecond laser is soon to become a universal light source – spanning any time scale and generating any wavelength of light. Starting from the wave-like properties of light, this book presents in a non-technical manner, with clear illustrations, and without formulas, what makes this class of lasers so versatile and the future of many more applications. Many of the subjects covered in this book are described in plain words for the first time.