This paper presents a technique of analysis, synthesis and optimization of stationary automatic control systems, which is based on the introduction of a concept of spectra, Problems of analytical equivalence of stability criteria of Routh, Hurwitz and Markov, of stability inversion algorithms for stationary systems, of generalized determinant stability indices and uniform stability margin in the senses of their criteria are considered, Integral stability criteria are formulated and some characteristics of the primary spectrumRn. which is uniquely related to the characteristic equation, are discussed, Finally, some properties are given of the integral quadratic measure used for solving the problem of performance inversion for stationary systems and for determining loci describing a continuum of quasioptimal stationary systems that are to meet given requirements concerning dynamical characteristics.