Foreword This work deals with the reliable numerical determination of fundamental properties of control systems that can be sufficiently accurately approximated by a linear model, which represents merely a first-order approximation. In addition to controllability and observability, properties such as invertibility, input-output decoupling, disturbance decoupling, and behavior under high feedback gains are the focus of interest. All these properties are fundamentally closely linked to appropriately defined zeros of the system. Therefore, a significant emphasis is placed on the treatment of the concept of finite and infinite zeros of multi-variable systems. Initially, a low-order model of a machine tool drive is used to demonstrate how strongly numerically determined statements are influenced by.