This Article Illustrates Howpolynomials and Polynomial Matrices Can Be Used to Describe Linear SysTems.The Focus Is Put on the Transformation to and from the State-Space Equations,Because It Is a Convenient Way to Introduce Gradually the Most Importantproperties of Polynomials and PolynoMial Matrices, Such As: Coprimeness,Greatest Common Divisors, Unimodularity, Column- and Row- Reducedness,Canonical Hermite or Popov Forms.