This paper presents a set of charts for synthesis and analysis of linear control systems in the frequency domain based on approximation to a third-order system, that is, a closed-loop transfer function with two complex poles, one real pole and one real zero. It involves the specifications of both open-loop and closed-loop systems. Since a set of similar charts for time domain have already been developed, this approach can be applied to most practical linear control systems, either in the frequency domain or the time domain. Three examples are given.