This book explores a range of direct and inverse problems associated with time-fractional and time-space (fully fractional) wave equations. In the context of direct problems, it addresses Cauchy problems and initial-boundary value problems. For inverse problems, the book examines both nonlinear inverse coefficient problems and linear inverse problems focused on determining coefficients on the right-hand sides of the equations. In the fractional wave equations, the fractional derivatives are expressed using various definitions, including the Riemann-Liouville, Caputo, Caputo-Dzhrbashyan, generalized Riemann-Liouville (Hilfer), conformable fractional derivatives, and Riesz operators. The book is intended for a broad audience of mathematicians specializing in fractional differential equations and the theory of inverse problems associated with them.