For the H∞ control problem of preview and delayed systems, a solvability condition and a control law are established in the output feedback setting. By employing the analytic solution of the corresponding operator Riccati equation, the solvability condition is characterized by maximal roots of transcendental equations. Furthermore it is shown that the control law for the general problem is constructed based on a predictive compensation law with an observer which is given by integro-differential equation. The structure of the typical control law is illustrated with control/filtering problems.