Subspace Identification of Dynamic Systems presents both the stable and unstable systems and also looks at the controller design of unstable systems. Different kinds of controller designing methods such as equating coefficients method, pole placement method, synthesis method and stability analysis method for both stable and unstable systems are described in details. The conventional identification methods such as process reaction curve method and optimization methods are illustrated. The parameter estimation of unstable system by the prediction error method alongwith the effects of sampling time, the noise level in the identification of the unstable systems are discussed. The subspace identification methods are described in detail and the steps involved in the algorithms, the MATLAB code for the subspace identification methods such as N4SID, MOESP, CVA and DSR methods are given. The modified MON4SID method is presented and this method is evaluated on several simulation case studies involving the stable and the unstable transfer function models. The experimental application of the modified MON4SID methods to a magnetic levitation system and an inverted pendulum system are given. This book can be used for postgraduate students in chemical, instrumentation and control engineering, and electrical engineering disciplines.