The subject of fractional calculus has applications in diverse and widespread fields of engineering and science such as electromagnetics, viscoelasticity, fluid mechanics, electrochemistry, biological population models, optics, and signals processing. It has been used to model physical and engineering processes that are found to be best described by fractional differential equations. The fractional derivative models are used for accurate modeling of those systems that require accurate modeling of damping. In these fields, various analytical and numerical methods including their applications to new problems have been proposed in recent years. In the present book, we present some fractional derivatives, integrals and solutions of fractional differential equations.