The book provides a comprehensive account of a wide selection of variational problems that include a fractional operator (a derivative or an integral in some cases). Both main formulations (Riemann-Liouville and Caputo) are treated in length and for them the authors derive the corresponding Euler-Lagrange equations and the fractional version of Noether's theorem. They also provide a thorough treatment of many details and extensions. Besides, they also consider other approaches and address the Hamiltonian formulation. The book has the great advantage of presenting an in-depth panoramic view of the field.