This is an applications paper reporting on the methodological basis and the development of a production-grade software package for use in the dynamic stability (or "small disturbance") analysis of large power systems. This package, known as EISEMAN (EIgenSystem Evaluation-Machine And Network), is capable of studying a wide range of dynamic stability phenomena, such as subsynchronous resonance, intermachine rotor oscillations, and the effects of excitation and turbine-governor systems on stability. All of the eigenvalues of the system are calculated, as well as desired eigenvalue sensitivities. A noteworthy feature of this eigenvalue-based tool is its capability of modeling to various degrees of detail the dynamics of the power system components-the network, synchronous machines and control systems. This tool can also be used to develop root locus plots and the frequency response characteristics of the power system. The present version of EISEMAN can be used for the analysis of systems containing up to 250 machines, 1,500 buses, 2,000 lines, and 500 dynamic states. Several test cases demonstrate the application of this tool.