This chapter has a special place in the book. Here we state and solve an initial boundary value problem describing an unsteady flow of a viscous fluid in the half-space above a rotating flat wall. A fluid rotates bodily with the wall bounding it at angular velocity ω0 = const about a direction not perpendicular to the wall. The unsteady flow is induced by the longitudinal oscillations of the wall. In this setting, the velocity field of the viscous flow tangent to the flat wall is found. The tangential stress vector acting from the fluid on the plate is also calculated. The solution is given in analytic form.