From the authors’ introduction: “We consider Riemannian or pseudo- Riemannian metrics of class \(C^{\infty}\) which are defined in an open set of \(R^ n\) (n\(\geq 4)\). It is an important problem to give a survey of all polynomial conformally invariant tensors which can be formed from the fundamental tensor and its derivatives of all orders, or with less pretension to give methods for constructing special classes of such tensors. It is the purpose of our paper to make some steps towards a solution of this problem.”